code: func (v *Validator) LengthRange(field string, min int, max int) *ValidationResult {
  	if val := v.data.Get(field); len(val) < min || len(val) > max {
  		return v.addLengthRangeError(field, min, max)
  	} else {
  		return validationOk
  	}
  }
docs: // LengthRange will add an error to the Validator if data.Values[field]
  // is shorter than min (if data.Values[field] has less than
  // min characters) or if data.Values[field] is longer than max
  // (if data.Values[field] has more than max characters), not
  // counting leading or trailing whitespace.