code: function formatChangesToXMLString(changes, shallow) {
              var properties = [];
  
              if (changes.changed == 'equal') {
                  return '';
              }
  
              var diff = changes.value;
  
              for (var key in diff) {
                  var changed = diff[key].changed;
                  if (changed !== 'equal')
                      properties.push(formatChange(key, diff[key], shallow, true));
              }
  
              return $sce.trustAsHtml('<span>' + openChar + '</span>\n<div class="diff-level">' + properties.join('<span>,</span>\n') + '\n</div><span>' + closeChar + '</span>');
  
          }
docs: Convert to a readable xml/html Json structure
  @param {Object} changes
  @return {string}
  @param shallow