docs: function detectCustomErrorMessage(key) {
              if (typeof properties[key] === 'object' && properties[key].errorMessage && properties[key].value) {
                  return properties[key];
              }
              else  if (_.isArray(properties[key])) {
                  return {
                      value: properties[key][0],
                      errorMessage: properties[key][1]
                  };
              }
              else {
                  return {
                      value: properties[key],
                      errorMessage: undefined
                  };
              }
          }