Ninja Forms Append Error Messages

gistfile1.php

function customnf_success_msg( $content ) {
   global $ninja_forms_processing;

   if( ! isset( $ninja_forms_processing ) )
       return $content;

   $success = '';
   if( $success = $ninja_forms_processing->get_all_success_msgs() ) {
       foreach( $success AS $id => $msg ) {
           $success .= $msg . '<br />';
       }
   }
   $error = '';
   if( $error = $ninja_forms_processing->get_all_errors() ) {
       foreach( $error AS $id => $msg ) {
           $error .= $msg . '<br />';
       }
   }

   if( !empty( $success ) OR !empty( $error ) ) {
       $new_content = '<div class="customnf-msgs">';
       if ( $success ) {
           $new_content .= $success;
       }
       if ( $error ) {
           $new_content .= $error;
       }
       $new_content .= '</div>';
       $content = $new_content . $content;
   }
   return $content;
}
add_filter( 'the_content', 'customnf_success_msg' );