for(key in person)
    {
         let value=person[key]
         Object.defineProperty(person,key,{           
                        
            get(){
                  return value
                 },
                        
            set(val)
                 {
                   value=val
                    _render(ul)
                  }
                   })
                    
                }
                
                inp.oninput=function(){
                    person.weight=this.value
                }