title: how to take 2d list from user in python?
body: <p>I want that user give input like this</p>
  <pre><code>[[3,4,5],[7,2,1]]
  </code></pre>
  <p>and it will create a 2d array automatically and store in a. so when print(a) will given it returns</p>
  <pre><code>a=[[3,4,5],[7,2,1]]
  </code></pre>
  <p>where type(a[0][0]) i mean all elements inside a will be int. How can I do it?</p>