code: func (m *MockEventService) RegisterBlockEvent(filter ...fab.BlockFilter) (fab.Registration, <-chan *fab.BlockEvent, error) {
  	eventCh := make(chan *fab.BlockEvent)
  	reg := &dispatcher.BlockReg{
  		Eventch: eventCh,
  	}
  	return reg, eventCh, nil
  }
docs: // RegisterBlockEvent registers for block events.