Pytest Global Variables

Using pytest with Django Posted on December 7, 2015 by Cameron Maske When it comes to testing in python pytest is my favorite testing tool. This is not trivially enforced, and it is easy to miss that the variable doesn't work (or partially misbehaves) when set too late. Global Variables. We won't bother doing any branching. One test might not clean-up this global state, the next test might not initiate all it's assumptions completely. By default, these are the only variables available to your build script. Modify your pylintrc to customize which errors or conventions are important to you. I am getting hard time in sending screenshot to reportportal. py einige Globale variable, und verwenden Sie es in tests. I'd like to share some of the tools and practices we're using at JetBridge to develop python web applications. These variables are controlled via pytest hooks. By Brij Mohan. A local variable is the opposite, it can only be accessed within its frame. (I have noticed that, despite its general awesomeness, pytest does have some strange quirks when it comes to general environment issues - the above for example, plus treatment of global variables). The monkeypatch fixture helps you to safely set/delete an attribute, dictionary item or environment variable or to modify sys. • pytest is a testing framework that is commonly used in the Python community. pytest exception for wrong column typeFlask-SQLAlchemy nullable=FalseDifference between except: and except Does an increasing sequence of reals converge if the difference of consecutive terms approaches zero?. • unittest is included in the Python standard library. I have two slightly different URLs set up as global variables on a profile that I am trying to figure out how to bind to the test suite (so the test case will be run multiple times against the differing URLs). A class can have more than one inner classes, but in general inner classes are avoided. Python Path and Version By default the extension uses the Python interpreter available in the current path. x syntax into valid 2. Consider parallelising test runs by default (there are several plugins available for this). Utility functions and pytest fixtures for testing are provided in sphinx. 0, we allow shortcut aliases used inside of functions and methods that are not called from any global scope code. Pytest documentation mostly highlights three scope levels namely: function, module, and session scopes, but there is another scope available, which is the class scope. PyTest: Auto delete temporary directory created with tmpdir_factory I'm trying to create a temporary directory with a specific name (eg, "data") for all tests within a module using PyTest's tmpdir_factory similar to the tutorial :. test and will take the same options. Variable Explorer dialogs through better length validation and garbage collection, and now skip the whole saving process entirely if the object was not modified (or cannot be modified). This will open the System Properties dialog. I’m still intending on supporting the plugins, but it feels good to have a larger team looking after them if needed. By default, pytest-bdd will use current module's path as base path for finding feature files, but this behaviour can be changed in the pytest configuration file (i. the pytest fixture solution. With thousands of browsers available in the market, automation testing for validating cross browser compatibility has. It is possible to extend this to a pytest plugin so that it runs even easier. test fixtures and parametrization to generate sequence graphs of a particular structure. 1 - Fix implementation of ‘auth’ keyword 0. testing will help your test implementation. Having such developed community and tools, it may seem that this topic should not leave much to discuss in the Python world. Such that I could say "AWS_PROFILE=foo" for my project foo, and any new Java, Bash, Node, whatever run config I create would default to using it. It's pretty easy to see that "import" defines a variable: >> type(os) What's a bit harder to understand is the idea that the global variables defined inside of our module all become attributes on the module object. x syntax, if a syntactical conversion is possible. The difference is that global variables can be accessed locally,. And as class variables, the state is divorced from many benefits offered by the object-oriented marriage between attributes and behaviors. --tb=no disables the python traceback which might be irrelevant unless the test script itself is debugged. pytest implements all aspects of configuration, collection, running and reporting by calling well specified hooks. To avoid code repetition, we can use pytest's fixtures:. This framework uses 'pytest-xdist' module to run multiple threads to run the tests at the same time depending on the number of available processor cores (2X of number of available cores). In Python, a variable declared outside of the function or in global scope is known as global variable. In the User variables section, click New. main import check_path, parse_options # Use and/or modify 0 or more of the options defined as keys in the # variable my_redefined_options below. This will open the Environment Variables dialog. • unittest is included in the Python standard library. ‘Undefined’ is the property of the global object. Selenium with Python Training Online course and free videos will help you learn python, WebDriver , pytest and framework with live projects & certification as well. You just type ‘name’ at the prompt and the code executes. Precautions while using Pytest. 2020-01-23T18:41:07Z https://bugs. These variables can be used by fixtures as well. In this article, Toptal Freelance Software Engineer Marcus McCurdy explores different approaches to solving this discord with code, including examples of Python m. For example, let a Computer Science Student be represented by class CSStudent. Python 2 Python 3 SageMath (Py 2) Anaconda 2019 (Py3) 3to2 Refactors valid 3. In this commit, those values will be maintained according to operations. Fixtures are meant to avoid using global variables in the. 1、在function中使用 2. Setting pytest options¶. When performing cross browser testing manually, one roadblock that you might have hit during the verification phase is testing the functionalities of your web application/web product across different operating systems/devices/browsers are the test coverage with respect to time. It's a proof that the code we've written works and it gets a safety net if we make any changes to our code in the future. the pytest fixture solution. A python_thrift_library generates Python code from. 05 for 5 percent): 0. If the function is not returning data, presumably its purpose is some side effect — so test for the side effect. pytest_plugins variables are processed recursively, so note that in the example above if myapp. Environment variables are used according to a specific precedence order, as follows: Environment variables declared inside a shell command in a run step, for example FOO=bar make install. Skip to end of metadata. Setting the path and environment variables will differ depending on the version of Windows you have on your computer. En plus flake8 peut mettre sa config dans les mêmes fichiers que pytest donc j’ai souvent ça:. This might be a global (process) variable, filesystem, etc. The environment variables should be provided by your test, not by your test runner. # 前置き データ連携のお仕事にも携わることになりまして、契約した企業へと自社データを提供するAPIを作りました。 画面で動く既存サービスもAPI構成にはなっており、そっちのWebAPIのテストはFrisby. Tal vez es la única manera?. Test status¶. Powerful data structures for data analysis, time series, and statistics. Hi Frank, I want to use the subprocess module to perform ssh connection to a linux server (using username and password) and I would like to navigate to a specific path and access (perform various operations on) the data/file in that path. Because of this, Python implements common integer values as singletons: that is, only one copy of these numbers exist in memory. These test metrics are very important and should be reflected in HP ALM to show the true health of any project. We need to bootstrap pytest with our Django project settings. Request and Response Objects ¶ Each responder in a resource receives a Request object that can be used to read the headers, query parameters, and body of the request. Secondly, in order to affect global scope, the variables need to be set before inherit. Python Path and Version. This can be useful to detect a test that passes just because it happens to run after an unrelated test that leaves the system in a favourable state. At the same time, fixtures are used differently from global variables. I'm hung up on a nice way to perform the teardown. I am getting hard time in sending screenshot to reportportal. These terms of global and local correspond to a variable's reach within a script or program. I want to create a pytest with a fake utcnow, but also I need to preserve the functionality of all other datetime methods. The following are code examples for showing how to use pytest. labgrid includes a pytest plugin to simplify writing tests which involve embedded boards. Pytest documentation mostly highlights three scope levels namely: function, module, and session scopes, but there is another scope available, which is the class scope. index() return the position of the character that you've passe view the full answer. This might be a global (process) variable, filesystem, etc. sleep(int) because there's a sleep method on all QThread objects which we can use. Fixtures are meant to avoid using global variables in the. fixture def graphql_client(): from myproject. In this case, the built-in input function is a value of python's __builtins__ dictionary, so we can alter it like so:. [EnvInject] - Inject global passwords. from pylava. Pytest documentation mostly highlights three scope levels namely: function, module, and session scopes, but there is another scope available, which is the class scope. pytest plugin for manipulating test data directories and files. One has to script their automation code in such a way that snap feature is supported. I'm hung up on a nice way to perform the teardown. After performing an action, you can make assertions about. pytest can be used for all types and levels of software testing. sleep(int) because there's a sleep method on all QThread objects which we can use. eu Feb 26, 2020. The same goes for other test cases, if you need to specify a flag to flake8 for some reason you would run tox -e flake8 -- --ignore XYYY where XYYY is the linter check you want to ignore. Fixtures are meant to avoid using global variables in the. copy_file_to_docker docker_exec_something = helpers. By using the parameters declaration, you can interpolate (or, "pass values") into reusable commands jobs and executors. yaml will then be available for formatting in all tests during that test run. Let's say you have a structure like this:. In a class level scope, we directly inject our environment into the class as instance variables, which are then shared among all the methods of the class. By the way pytest-play is automatically released on PyPI thanks to travis when a new tag comes on the master branch. Testing Python Applications with Pytest. Using the -vv option will show a separate line for each test and whether it has passed or failed as well as showing more information about mismatches in data returned vs data expected; Using --tb=short will reduce the amount of data presented in the traceback when a test fails. In other words, you can use predefined variables / project / group or environment-scoped variables to define an expression GitLab is going to evaluate in order to decide whether a job should be created or not. magics = True first. Be aware that if you do pass in a new default module, it entirely replaces the Django defaults, so you must specify a value for every possible setting that might be used in that code you are importing. In this case, the built-in input function is a value of python's __builtins__ dictionary, so we can alter it like so:. These test metrics are very important and should be reflected in HP ALM to show the true health of any project. org and select the most recent […]. test hooks to set (or reset) your global variable(s) as appropriate. • unittest is included in the Python standard library. An inner class can have both methods and variables. Java, on the other hand, is a statically-typed language, which means variable types should be declared explicitly. This is where the actual snap feature logic is present. global_variable_1 to 100. Pytest dbfixtures is a pytest plugin that makes it a lot easier to set up proper database or storage engine for testing. While in many or most other programming languages variables are treated as global if not otherwise declared, Python deals with variables the other way around. And class may also have non-static members like name and roll. If the function is not returning data, presumably its purpose is some side effect — so test for the side effect. Unit test frameworks like unittest and pytest take this. Page Object Model Framework for Selenium in pytest, python and allure reporting View on GitHub Selpy-Python. the pytest fixture solution. Automated tests. This will open the Environment Variables dialog. Choose a link below for your version of Windows. Example: Selenium, JUnit, Pytest, TestNG, Visual Studio Test, etc. These variables are controlled via pytest hooks. In this commit, those values will be maintained according to operations. PYtest ( C-Urea breath test) is indicated for use in the detection of gastric urease as an aid in the diagnosis of H. I was wondering - is there a way to use PM as a singleton / module variable / global variable so I can instantiate it just with the project_name anywhere in the code without having direct access to the PM instance that was created in the host app? When I read the docs, I thought it could be possible but I found out it's probably not. Global state There are two sources of global state when using pytest inside the notebook: pytest will find any test function ever defined. The variables in common. py Run tests in a directory pytest testing/ Run tests by keyword expressions pytest -k "MyClass and not method" This will run tests which contain names that match the given string expression, which can include Python operators that use filenames, class names and function names as variables. When logging a message,. Prior to pytest version 2. It's too late. With this information, you are now ready to step through some tests using the TDD method. 0 the pytest global variable became deprecated. This mechanism makes it easy to share fixtures within applications or even external applications without the need to create external plugins using the setuptools 's entry. 0 you could only enter PDB tracing if you disabled capturing on the command line via pytest-s. %%rewrite_asserts. Parameters. ‘Undefined’ is the property of the global object. These variables are controlled via pytest hooks. As mentioned above, using the decorator or context manager provides access to the mocked function via an additional variable. A possible solution to this could be creating a bunch of global variables to hold these values but that practice is generally frowned upon with good cause. Secondly, in order to affect global scope, the variables need to be set before inherit. To ensure this, each test function should create and destroy it's context. When you do that, the information. Building a software project. We won't bother doing any branching. This doesn’t guarantee variables are used correctly; one example I’ve seen firsthand was the same value (admin and support email addresses) assigned to two environment variables, and misused in the mailer. The _get_top_post is just copied from the original reddit code and the run method goes over the self. Either configure() or DJANGO_SETTINGS_MODULE is required ¶ If you’re not setting the DJANGO_SETTINGS_MODULE environment variable, you must call configure() at some point before using any code that reads settings. Pytest Introduction. eu Feb 12, 2020. When an airplane is flying, the black box will record flight data. The variables keyword is used to define variables expressions. local variables in functions def someFunction(): # global f f = 'I am learning Python' print(f) someFunction() print(f) Using the keyword global, you can reference the global variable inside a function. # Declare a variable and initialize it f = 101 print(f) # Global vs. Perhaps it only happens for some values. sleep(int) because there's a sleep method on all QThread objects which we can use. Recently I had to install Python on Windows 10, so I could use the "Closure Linter" tool for PhpStorm. How can I automatically delete the temporary directory "data" after the pytest tests finish? The tmpdir argument creates temporary directory that is removed but it doesn't have a name and it only has function scope. parametrize part. Function-level fixture parametrization (or, some pytest magic) 15 Nov 2017. Skip to end of metadata. It allows you to replace parts of your system under test with mock objects and make assertions about how they have been used. TDD, in its most basic terms, is the process of implementing code by writing your tests first, seeing them fail, then writing the code to make the tests pass. The pytest framework makes it easy to write small tests, yet scales to support complex functional testing for applications and libraries. --global can accept a comma-delimited list; --global app,YUI is equivalent to --global app --global YUI. Same as the %%run_pytest, but cleans any previously found tests, i. : [pytest] timeout = 300 The PYTEST_TIMEOUT environment variable sets a global timeout overriding a possible value in the configuration file. A list of default query processing options is established for the duration of a user's work session. Heavy usage of global state or context: instead of explicitly passing (height, width, type, wood) to each other, Table and Carpenter rely on global variables that can be modified and are modified on the fly by different agents. yaml will then be available for formatting in all tests during that test run. An example of a simple test:. For more examples and API details, see the official Pickle use documentation. Python 2 Python 3 SageMath (Py 2) Anaconda 2019 (Py3) 3to2 Refactors valid 3. Instead of moving the resource_a related fixtures and tests into a class, we: Import pytest; Use the pytest fixture decorator to specify ‘resource_a_setup()’ as a fixture. Anonymous said: Not sure if some can help same for JAVA+TEsngNG. A function’s implicit context is made up of any of the global variables or items in the persistence layer that are accessed from within the function. test import Client return Client(schema). Part 1, part 2 and part 3 looked at some background to why Pytest does something unusual and the principles behind how it works. If you are a pytest user though I encourage you to have a look at the excellent pytest-mock library. This framework uses 'pytest-xdist' module to run multiple threads to run the tests at the same time depending on the number of available processor cores (2X of number of available cores). However, it's possible that this invariant will be broken at some point: perhaps there is a typo in one of the methods, or perhaps some other bit of code gets in and fiddles with the private variables, etc. The above example temporarily sets the working directory relative to the script itself (using the special __file__ variable). pytest provides a way to use some global variables within the session. This will open the Environment Variables dialog. If the function is not returning data, presumably its purpose is some side effect — so test for the side effect. In Python, a variable declared outside of the function or in global scope is known as global variable. Si parla dell’ovvio e meno magico opzione: l’utilizzo di un apparecchio. because it's a less verbose but just as powerful approach to writing tests (pytest). pytest Documentation Release 5. Our client is a global Tier 1 company involved in many leading mission critical projects. Please follow the subs rules and guidelines when you do post there, it'll help you get better answers faster. Complete documentation for ActivePython 3. You still have access to all global variables from * the test. myplugin also declares pytest_plugins, the contents of the variable will also be loaded as plugins, and so on. A test is a code that checks the validity of other code to see if something is working (or not working). To avoid code repetition, we can use pytest's fixtures:. This will get us acquainted with how pytest works, and we'll get comfortable with the most basic git commands: git status, git commit, and git push. But when i use xdist to run my test in parallel , These global variables are not updated Here is my confte. All the other extensions need to be explicitly enabled via pytest flag to have an impact, so are safe to install. perform a set of setup tasks, then return some working data. In the User variables section, click New. Let's say you have a structure like this:. Simply use one of provided fixtures that start predefined clean database server for your tests or creates server more tailored for your application by using one of provided factories. We need to bootstrap pytest with our Django project settings. path for importing. This will open the System Properties dialog. You can vote up the examples you like or vote down the ones you don't like. pytest implements all aspects of configuration, collection, running and reporting by calling well specified hooks. Changing global variable from a function; Global variables mutable in functions; Scoping issues; sub in sub; Scoping sub in sub (enclosing scope) Function objects; Functions are created at run time; Mutable default; Use None as default parameter; Inner function created every time the outer function runs; Static variable; Static variable in. bat and on macOS and Linux with build. And this is the truly wonderful aspect of pytest, the use of plugins to tailor it to be the tool you need it to be and. Python 2 Python 3 SageMath (Py 2) Anaconda 2019 (Py3) 3to2 Refactors valid 3. D uring my work as Python developer, I have seen many different approaches to software testing. In my work my more recent work with de Bruijn graphs, I've been making heavy use of py. Variable inside of functions and methods. While in many or most other programming languages variables are treated as global if not otherwise declared, Python deals with variables the other way around. Global Variables. [Roundup-checkins] [PATCH 6 of 7] Work-around for pytest. Simply use one of provided fixtures that start predefined clean database server for your tests or creates server more tailored for your application by using one of provided factories. This framework uses 'pytest-xdist' module to run multiple threads to run the tests at the same time depending on the number of available processor cores (2X of number of available cores). This is an issue I came across when trying to write a test to ensure a configuration is correctly read from a number of environment variables: It can be tricky when module global variables are part of the setup. Currently, AuditMode and DeployedMode are defined but not implemented. from pylava. The test utilizes a liquid scintillation counter for. Click on a list name to get more information about the list, or to subscribe, unsubscribe, and change the preferences on your subscription. This means, global variable can be accessed inside or outside of the function. Get Live Perl Training from Experts in Marathahalli & BTM. That cause the memory leak. test fixtures and parametrization to generate sequence graphs of a particular structure. I'd like to share some of the tools and practices we're using at JetBridge to develop python web applications. But when i use xdist to run my test in parallel , These global variables are not updated Here is my confte. The monkeypatch fixture helps you to safely set/delete an attribute, dictionary item or environment variable, or to modify sys. A local variable is the opposite, it can only be accessed within its frame. A Simple First Example with Pytest. I'll write about that in a future post. 416666666666666666666666. Includes 4 hours of video and lots of hands-on exercises! Buy for $150. This mechanism makes it easy to share fixtures within applications or even external applications without the need to create external plugins using the setuptools 's entry. Only pytest-sugar will automatically change pytest's behavior (in a nice way), so remove it from the list if you don't like it. A test is a code that checks the validity of other code to see if something is. Because the graphql client will be reused across the django site, I added a global fixture that will automatically load mty project's schema. Global state There are two sources of global state when using pytest inside the notebook: pytest will find any test function ever defined. This can be useful to detect a test that passes just because it happens to run after an unrelated test that leaves the system in a favourable state. In this article, Toptal Freelance Software Engineer Marcus McCurdy explores different approaches to solving this discord with code, including examples of Python m. yaml will then be available for formatting in all tests during that test run. Selenium with Python Training Online course and free videos will help you learn python, WebDriver , pytest and framework with live projects & certification as well. The real advantage of pytest comes by writing pytest test cases. from pylava. An inner class or nested class is a defined entirely within the body of another class. SKIPNAMES that can be extended for that purpose, though this seldom shall be needed (except for own pytest plugins, as shown in the example mentioned above). Let's see an example on how a global variable is created in Python. Mocking built-in functions and environment variables. fixture def graphql_client(): from myproject. From building custom TCP servers to large-scale finance apps, Naftuli's breadth of experience makes him a top-of-class dev and sysadmin. schema import schema from graphene. The variables in common. The global variable CWD (Current Working directory): which is most likely going to be used to reference the routers configuration file location Example: # For all registered routers, load the zebra configuration file for rname , router in router_list. jsで書いてみたりし. Note: In the context of this article, a bound variable is an argument to a lambda function. It just allows you to link tests to existing tickets. pi as whole can be imported into our intial code, rather than importing the whole module. Local Variables: Any variable declared inside a function is known as a local variable. Note: In the context of this article, a bound variable is an argument to a lambda function. En plus flake8 peut mettre sa config dans les mêmes fichiers que pytest donc j’ai souvent ça:. A global variable is one that can be accessed anywhere. What Is Test-Driven Development? This approach allows you to escape the trap that many developers fall into. But when i use xdist to run my test in parallel , These global variables are not updated Here is my confte. A pytest plugin for JIRA integration. For example, let a Computer Science Student be represented by class CSStudent. eu Feb 26, 2020. Most likely using only modified on this branch trick to incrementally enforce it until we can use the pytest-mypy plugin. Python 2 Python 3 SageMath (Py 2) Anaconda 2019 (Py3) 3to2 Refactors valid 3. pytest Documentation Release 5. test and will take the same options. patch to replace that method with a mock f. Use monkeypatch. Jest unit test - global variable modified in a fun How to put invalid id to get request?. Instead of moving the resource_a related fixtures and tests into a class, we: Import pytest; Use the pytest fixture decorator to specify 'resource_a_setup()' as a fixture. A much better solution for global state is the singleton pattern. Now it's time to look into the implementation. Variable Energy Cyclotron Centre, Kolkata: Accelerator Physics, Condensed Matter Physics and Materials Science, Nuclear Physics (Experiments and Theory), Relativistic Heavy Ion Collisions (Experiments, Theory, QCD and QGP), and Physics of Neutrinos (Experiments). This can be used to disable some ajax operations, for example. # A pytest hook, called by pytest automatically - used to extract test case data and append it to the data global variable defined above. And in many ways, it's similar to what you'd get if you were to define a global variable by the name of "simple_file". Tick this checkbox to set up a list of new environment variables prefixed with 'ContinuaCI. The expectation is that on a multi-core machine a multithreaded code should make use of these extra cores and thus increase overall performance. FlaskCliRunner (app, This only works in single-threaded systems without any concurrency as it changes the global interpreter state. Click on a list name to get more information about the list, or to subscribe, unsubscribe, and change the preferences on your subscription. Request and Response Objects ¶ Each responder in a resource receives a Request object that can be used to read the headers, query parameters, and body of the request. Use fixtures for temporary file handling and cleanup More automated test skipping based on what's actually compiled. line 46: unittest. At the same time, fixtures are used differently from global variables. Because of this, Python implements common integer values as singletons: that is, only one copy of these numbers exist in memory. parametrize part. Many projects - amongst them Mozilla and Dropbox - switched from unittest or nose to pytest. This allows us to call our script from any directory and the relative file path will still work as desired. ├── data/ │ └── hello. You'll learn how to leverage OS services, code graphical application interfaces, create modules and run unit tests, define classes, interact with network series, query databases, and processes XML data. dll, the global variable can be destroyed when calling PyDict_DelItemString to delete the module. These were the latest versions when this post was written, be sure to check pypi if either pytest or pytest-django have been updated. iteritems (): router. # Declare a variable and initialize it f = 101 print(f) # Global vs. Download Python The first step is to download Python from python. Choose a link below for your version of Windows. (At least no regression. The --timeout command line option sets a global timeout overriding both the environment variable and. Using the -vv option will show a separate line for each test and whether it has passed or failed as well as showing more information about mismatches in data returned vs data expected; Using --tb=short will reduce the amount of data presented in the traceback when a test fails. You can vote up the examples you like or vote down the ones you don't like. usefixtures('big_dict') in modulo, ma poi non essere nel vostro spazio dei nomi in modo esplicito la richiesta potrebbe essere meglio. Fully customizable. How to set the path and environment variables in Windows Updated: 01/31/2019 by Computer Hope Setting the path and environment variables will differ depending on the version of Windows you have on your computer. A module is just a script that contains a bunch of definitions and declarations (you define classes and functions, and declare variables). In pytest any conftest. If you have any questions, comments or suggestions, feel free to ping me on twitter or gitter. It doesn’t actually install separate copies of Python,. This will open the Environment Variables dialog. To avoid code repetition, we can use pytest's fixtures:. In each iteration, trial candidates are. This global-seeming access to context may feel dirty to some, likely conditioned by a healthy aversion to global variables or “god-objects” because of thread safety issues, poor code organization, and the inability to grapple with multiple instances of such objects simultaneously in the same program. This issue is now closed. global_variable_1 to 100. Where ${env. A free variable can be a constant or a variable defined in the enclosing scope of the function. ‘Undefined’ is the property of the global object. # tests/conftest. The style recommendations for them are similar to those on function annotations described above: Annotations for module level variables, class and instance variables, and local variables should have a single space after the colon. Python Path and Version. For example, I need to parse a kubectl output in a task to extract the cluster service ip dinamically in order to configure a DNS name for an nginx ingress controller. cfg; Applying marks to @pytest. Welcome to another python 3 basics tutorial, in this tutorial we're going to now discuss the concept of global and local variables. By default, pytest-bdd will use current module's path as base path for finding feature files, but this behaviour can be changed in the pytest configuration file (i. If the function is not returning data, presumably its purpose is some side effect — so test for the side effect. The monkeypatch fixture helps you to safely set/delete an attribute, dictionary item or environment variable or to modify sys.