code: func (s *StepperDriver) SetDirection(direction string) error {
  	direction = strings.ToLower(direction)
  	if direction != "forward" && direction != "backward" {
  		return errors.New("Invalid direction. Value should be forward or backward")
  	}
  
  	s.mutex.Lock()
  	s.direction = direction
  	s.mutex.Unlock()
  	return nil
  }
docs: // SetDirection sets the direction in which motor should be moving, Default is forward