def channelOpen(self, ignored):
        """
        When the request to open a new channel to run this command in succeeds,
        issue an C{"exec"} request to run the command.
        """
        command = self.conn.sendRequest(
            self, b'exec', NS(self._command), wantReply=True)
        command.addCallbacks(self._execSuccess, self._execFailure)

        When the request to open a new channel to run this command in succeeds,
        issue an C{"exec"} request to run the command.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/endpoints.py