docs: function(params, callback) {
          /**
           * Callback for QB.users.listUsers(params, callback)
           * @callback listUsersCallback
           * @param {object} error - The error object
           * @param {object} response - Object with Array of users
           */
          var message = {}, filters = [], item;
  
          if (typeof params === 'function' && typeof callback === 'undefined') {
              callback = params;
              params = {};
          }
  
          if (params && params.filter) {
              if (Utils.isArray(params.filter)) {
                  params.filter.forEach(function(el) {
                      item = generateFilter(el);
                      filters.push(item);
                  });
              } else {
                  item = generateFilter(params.filter);
                  filters.push(item);
              }
              message.filter = filters;
          }
  
          if (params.order) {
              message.order = generateOrder(params.order);
          }
  
          if (params.page) {
              message.page = params.page;
          }
  
          if (params.per_page) {
              message.per_page = params.per_page;
          }
  
          this.service.ajax({
              url: Utils.getUrl(config.urls.users), data: message}, callback);
      }