docs: def request_forward_agent(self, handler):
          """
          Request for a forward SSH Agent on this channel.
          This is only valid for an ssh-agent from OpenSSH !!!
  
          :param function handler:
              a required handler to use for incoming SSH Agent connections
  
          :return: True if we are ok, else False (at that time we always return ok)
  
          :raises: SSHException in case of channel problem.
          """
          if self.closed or self.eof_received or self.eof_sent or not self.active:
              raise SSHException('Channel is not open')
  
          m = Message()
          m.add_byte(cMSG_CHANNEL_REQUEST)
          m.add_int(self.remote_chanid)
          m.add_string('auth-agent-req@openssh.com')
          m.add_boolean(False)
          self.transport._send_user_message(m)
          self.transport._set_forward_agent_handler(handler)
          return True