def ssh_CHANNEL_FAILURE(self, packet):
        """
        Our channel request to the other side failed.  Payload::
            uint32  local channel number

        Get the C{Deferred} out of self.deferreds and errback it with a
        C{error.ConchError}.
        """
        localChannel = struct.unpack('>L', packet[:4])[0]
        if self.deferreds.get(localChannel):
            d = self.deferreds[localChannel].pop(0)
            log.callWithLogger(self.channels[localChannel],
                               d.errback,
                               error.ConchError('channel request failed'))

        Our channel request to the other side failed.  Payload::
            uint32  local channel number

        Get the C{Deferred} out of self.deferreds and errback it with a
        C{error.ConchError}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/ssh/connection.py