code: function createCheckEmail(fieldDefinition, fieldName) {
    const severity = propertyHelper.getSeverity(fieldDefinition);
  
    // return getIteratorFunction: function (fieldName, defaultValue, checkProperties, checkFunction, getErrorFunction,
    // 	getValueIfErrorFunction, getValueIfOkFunction) {
  
    let errorInfo = {
      severity: severity,
      errorCode: 'NOT_EMAIL'
    };
  
    return functionHelper.getParserCheck(errorInfo, getEmailIfValid, fieldName, undefined);
  
  }
docs: Checks if a given string looks like a valid email.
  @param fieldDefinition The field_definition for this field.
  @param fieldName The name of the current field
  @return The check