code: function normalizeArgs(arg1, arg2, arg3) {
      // assume most complex arg signature as default.
      var body = arg2;
      var callback = arg3;
  
      if (typeof arg2 === 'function') {
          callback = arg2;
          body = null;
      }
  
      return {
          body: body,
          callback: callback
      };
  }
docs: normalize variadic signatures for all the method actions.
  normalizeArgs({...}, cb);
  normalizeArgs({...}, body, cb);
  @private
  @function normalizeArgs
  @param   {Object}   arg1 options object
  @param   {Object}   arg2 output body
  @param   {Function} arg3 callback function
  @returns {Object}        normalized args