code: func (cc *Client) RegisterChaincodeEvent(chainCodeID string, eventFilter string) (fab.Registration, <-chan *fab.CCEvent, error) {
  	// Register callback for CE
  	return cc.eventService.RegisterChaincodeEvent(chainCodeID, eventFilter)
  }
docs: // RegisterChaincodeEvent registers for chaincode events. Unregister must be called when the registration is no longer needed.
  //  Parameters:
  //  chaincodeID is the chaincode ID for which events are to be received
  //  eventFilter is the chaincode event filter (regular expression) for which events are to be received
  //
  //  Returns:
  //  the registration and a channel that is used to receive events. The channel is closed when Unregister is called.