title: Python convert string of characters into proper list structure
body: <p>I have a string variable,</p>
  
  <pre><code>str = "b'[["innovation",3],["marketing",3],["credentials",2],["trends",2]]'
  </code></pre>
  
  <p>What's the best way to convert them into easy-to-process python structures like <code>json/dict/list/tuple</code>?</p>