Django Cheatsheet

decorators.py

class SuppressExceptionsDecorator:
    """Decorator for temporarily suppressing specified exceptions.

    Exception suppression is limited to the function execution.

    Example:
        ```python
        import warnings
        @SuppressErrorsDecorator(MyException)
        def foo():
            raise MyException("bar")
        foo()  # this function call should not raise `MyException`.
        ```
    """

    def __init__(self, *exceptions: Exception) -> None:
        """Decorator constructor that saves the exceptions to be suppressed.

        Arguments:
            exceptions: the exceptions to be suppressed during the
                execution of the decorated Callable.
        """
        self.exceptions = exceptions

    def __call__(self, func: Callable) -> Callable:
        """Decorator for temporarily suppressing specific exceptions during the
        execution of the decorated Callable.

        Implementing the `__call__` method makes the class callable.
        
        See:
        	https://docs.python.org/3/reference/datamodel.html#emulating-callable-objects

        Arguments:
            func:
            	The Callable to be decorated.
        Returns:
            The decorated Callable, which suppresses the specified exceptions
            during its execution time.
        """

        @functools.wraps(func)
        def wrapper(*args: Any, **kwargs: Any) -> Any:
            """Wrapped function to be returned by the decorator.
            
            Arguments:
                args:
                	Original Callable arguments.
                kwargs:
                	Original Callable keyword arguments.

            Returns:
                Original Callable evaluation return values.
            """
            try:  # exception suppression limited to this code block
                return func(*args, **kwargs)  # evaluate Callable
            except self.exceptions:  # register exceptions to be suppressed
                pass

        return wrapper  # return decorated Callable


class SuppressWarningsDecorator:
    """Decorator for temporarily suppressing specified warnings.
    
    Warning suppression is limited to the function execution.

    See:
    	https://docs.python.org/3/library/warnings.html#temporarily-suppressing-warnings

    Example:
        ```python
        import warnings
        @SuppressWarningDecorator(MyWarning)
        def foo():
            warnings.warn("bar", MyWarning)
        foo()  # this function call should not raise `MyWarning`.
        ```
    """

    def __init__(self, *warnings: Warning) -> None:
        """Decorator constructor that saves the warnings to be suppressed.
 
        Arguments:
            warnings:
            	The warnings to be suppressed during the
                execution of the decorated Callable.
        """
        self.warnings = warnings

    def __call__(self, func: Callable) -> Callable:
        """Decorator for temporarily suppressing specific warnings during the
        execution of the decorated Callable.
        
        Implementing the `__call__` method makes the class callable.
        
        See:
        	https://docs.python.org/3/reference/datamodel.html#emulating-callable-objects

        Arguments:
            func: the Callable to be decorated.

        Returns:
            Callable: the decorated Callable, which suppresses the specified warnings
                during its execution time.
        """

        @functools.wraps(func)
        def wrapper(*args: Any, **kwargs: Any) -> Any:
            """Wrapped function to be returned by the decorator.

            Arguments:
                args:
                	Original Callable arguments.
                kwargs:
                	Original Callable keyword arguments.

            Returns:
                Any: original Callable evaluation return values.
            """
            with catch_warnings():  # warning suppression limited to this code block
                for warning in self.warnings:  # register warnings to be suppressed
                    simplefilter("ignore", category=warning)
                return func(*args, **kwargs)  # evaluate Callable

        return wrapper  # return decorated Callable

django_cheatsheet.py

# Add users to Group
group.user_set.add(*django_users)  # where `django_users` is a list of `django.contrib.auth.models.User`s