def test_increment(self):
        """
        Test incrementing a variable: L{MemCacheProtocol.increment} returns a
        L{Deferred} which is called back with the incremented value of the
        given key.
        """
        return self._test(
            self.proto.increment(b"foo"), b"incr foo 1\r\n", b"4\r\n", 4)

        Test incrementing a variable: L{MemCacheProtocol.increment} returns a
        L{Deferred} which is called back with the incremented value of the
        given key.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_memcache.py