docs: def _handle_connect(self, sid, namespace):
          """Handle a client connection request."""
          namespace = namespace or '/'
          self.manager.connect(sid, namespace)
          if self.always_connect:
              self._send_packet(sid, packet.Packet(packet.CONNECT,
                                                   namespace=namespace))
          fail_reason = None
          try:
              success = self._trigger_event('connect', namespace, sid,
                                            self.environ[sid])
          except exceptions.ConnectionRefusedError as exc:
              fail_reason = exc.error_args
              success = False
  
          if success is False:
              if self.always_connect:
                  self.manager.pre_disconnect(sid, namespace)
                  self._send_packet(sid, packet.Packet(
                      packet.DISCONNECT, data=fail_reason, namespace=namespace))
              self.manager.disconnect(sid, namespace)
              if not self.always_connect:
                  self._send_packet(sid, packet.Packet(
                      packet.ERROR, data=fail_reason, namespace=namespace))
              if sid in self.environ:  # pragma: no cover
                  del self.environ[sid]
              return False
          elif not self.always_connect:
              self._send_packet(sid, packet.Packet(packet.CONNECT,
                                                   namespace=namespace))