code: func (f *stateFlag) Set(s string) error {
  	i, err := common.GetState(s)
  	if err != nil {
  		return errors.Reason("value must be a valid state returned by get-states").Err()
  	}
  	*f = stateFlag(i)
  	return nil
  }
docs: // Set stores a new state in this flag, overriding any existing state.