def close():
        """
        Close the file.

        This method returns nothing if the close succeeds immediately, or a
        Deferred that is called back when the close succeeds.
        """

        Close the file.

        This method returns nothing if the close succeeds immediately, or a
        Deferred that is called back when the close succeeds.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/interfaces.py