title: How to create nested list in python with oop?
body: <p>I try to write a shopping program in python. so i need to categorizing shopping item as default or new category that user adding like below:
   1- user can add  category and item also update them.</p>
  
  <pre><code>shop  = [category1[ [item name : apple , count : 2 , price:1$],[item name :orange , count :2 , price:3]],category2[[item name : spoon , count :2 , price :3],[item name :fork , count :4 , price:5]]]
  </code></pre>