def write(self, data):
        """
        Write the given request body bytes to the transport using chunked
        encoding.

        @type data: C{bytes}
        """
        if self.transport is None:
            raise ExcessWrite()
        self.transport.writeSequence((networkString("%x\r\n" % len(data)),
            data, b"\r\n"))

        Write the given request body bytes to the transport using chunked
        encoding.

        @type data: C{bytes}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/_newclient.py