title: Python: Convert nDimensions list to string and vice versa
body: <p>My question is probably simple but I don't be able to figure it out.</p>
  
  <p>Consider this code where mylist can have any number of dimension:</p>
  
  <pre><code>mylist = [[1,2,3,4],[5,6,7]]
  mylist
  [[1,2,3,4],[5,6,7]]
  </code></pre>
  
  <p>It's easy to cconvert it to string:</p>
  
  <pre><code>myString = str(myList)
  myString
  &gt;'[[1,2,3,4],[5,6,7]]'
  </code></pre>
  
  <p>But how to easily convert it back to the same list ?
  I never get it work in any situation using .join or .split.
  I want it work in any case of the list was configured.</p>
  
  <p>thanks</p>