Apply a list of decorators to a given function.

    ``decorators`` may contain items that are ``None`` or ``False`` which will
    be ignored.

def _apply_decorators(func, decorators):
    """Apply a list of decorators to a given function.

    ``decorators`` may contain items that are ``None`` or ``False`` which will
    be ignored.
    """
    decorators = filter(_is_not_none_or_false, reversed(decorators))

    for decorator in decorators:
        func = decorator(func)

    return func