def count():
        """
        Return the number of opened file descriptors.

        @return: The number of opened file descriptors; this will be
            zero if this instance has not opened any.
        @rtype: L{int}
        """

        Return the number of opened file descriptors.

        @return: The number of opened file descriptors; this will be
            zero if this instance has not opened any.
        @rtype: L{int}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_tcp.py