code: function() {
      var args = this.store.utils.args(arguments)
      if (args.length > 1) {
        return this.validateFieldsHelper(args, this.validatesPresenceOf)
      }
  
      var field = args[0]
  
      if (Array.isArray(field)) {
        return this.validateFieldsHelper(field, [], this.validatesPresenceOf)
      }
  
      return this.validates(field, function() {
        var valid = this[field] != null
        if (!valid) this.errors.add(field, 'should be present')
        return valid
      })
    }
docs: This validator checks the given field`s value is not null.
  @class Definition
  @method validatesPresenceOf
  @param {array} fields - The fields to validate
  
  @return {Definition}