code: function(field, length) {
      if (Array.isArray(field)) {
        return this.validateFieldsHelper(field, [length], this.validatesLengthOf)
      }
  
      return this.validates(field, function() {
        var valid = true
        if (this[field]) valid = this[field].length <= length
        if (!valid)
          this.errors.add(field, 'maximum length of ' + length + ' exceeded')
        return valid
      })
    }
docs: This validator checks if the given field`s values length is lesss than or equal `length`.
  @class Definition
  @method validatesLengthOf
  @param {string} field - The field to validate
  @param {integer} length - The maximum length
  
  @return {Definition}