let funModule = (function () {    
  return {    
    isCuteMixin: function (obj) {    
      obj.isCute = function() {    
        console.log(true);    
      };    
    },    
    singMixin: function(obj) {    
      obj.sing = function() {    
        console.log("Flying, wooosh!");    
      };    
    }    
  };    
}) (); // 两个括号导致函数立即被执行