code: func EnumFail(name, in string, value interface{}, values []interface{}) *Validation {
  	var msg string
  	if in == "" {
  		msg = fmt.Sprintf(enumFailNoIn, name, values)
  	} else {
  		msg = fmt.Sprintf(enumFail, name, in, values)
  	}
  
  	return &Validation{
  		code:    EnumFailCode,
  		Name:    name,
  		In:      in,
  		Value:   value,
  		Values:  values,
  		message: msg,
  	}
  }
docs: // EnumFail error for when an enum validation fails