code: function(userId, properties, callback) {
        if (!userId) return callback(new Error(utils.i18n.identities.id));
        if (!properties.display_name) return callback(new Error(utils.i18n.identities.displayName));
        utils.debug('Identity replace: ' + userId);
  
        request.put({
          path: '/users/' + userId + '/identity',
          body: properties
        }, callback || utils.nop);
      }
docs: Replace all Identity properties. NOTE: The display_name property is required.
  
  @param  {String}   userId          User ID
  @param  {Object}   properties      Hash of properties to update
  @param  {Function} callback        Callback function