code: func (b *Driver) CounterClockwise(val int) error {
  	b.pcmdMutex.Lock()
  	defer b.pcmdMutex.Unlock()
  
  	b.Pcmd.Flag = 1
  	b.Pcmd.Yaw = validatePitch(val) * -1
  	return nil
  }
docs: // CounterClockwise tells drone to rotate in a counter-clockwise direction.
  // Pass in an int from 0-100.