code: function allowOptionalParams(params, callback) {
      if (!callback) {
          callback = params;
          params = { };
      }
      return {
          params: params,
          callback: callback,
      };
  }
docs: Allow 'params' to be optional, thus user can pass 'callback' in its place.
  
  @public
  
  @param {*} params - user's params
  @param {Function} [callback] - user's callback
  @return {Object} args
  @return {Function} args.callback
  @return {Function} args.params