/// <summary>
 /// Appends the given HTML to the form field.
 /// </summary>
 /// <param name="html">The HTML to append</param>
 /// <param name="config">Field configuration to update</param>
 /// <returns>The instance of <see cref="IFieldConfiguration"/> to allow for method chaining</returns>
 public static IFieldConfiguration Append(this IFieldConfiguration config, Func <object, IHtmlString> html)
 {
     if (config != null)
     {
         return(config.Append(html(null)));
     }
     return(null);
 }