Better to ask for forgiveness...

forgive.py

import contextlib
import functools

@contextlib.contextmanager
def forgiveness(exceptions):
    """Seek forgiveness

    """
    try:
        yield
    except exceptions:
        pass

class PermissionDenied(Exception):
    pass

@contextlib.contextmanager
def askfor():
    """Used to ask for permission

    """
    try:
        yield
    except PermissionDenied:
        pass

@contextlib.contextmanager
def permission(callable):
    """Give permission to proceed

    """
    if callable():
        yield
    else:
        raise PermissionDenied()

if __name__ == '__main__':
    import os
    with forgiveness(FileExistsError):
        print("Trying to create /tmp/foo")
        os.mkdir("/tmp/foo")

    print("Look no exception, forgiveness was given!")

    with askfor(), permission(lambda: not os.path.isdir("/tmp/bar")):
        print("Permission given to create /tmp/bar")
        os.mkdir("/tmp/bar")