title: Find indexes of common items in two python lists
body: <p>I have two lists in python list_A and list_B and I want to find the common item they share. My code to do so is the following:</p>
  
  <pre><code>both = []
  for i in list_A:
      for j in list_B:
          if i == j:
              both.append(i)
  </code></pre>
  
  <p>The list common in the end contains the common items. However, I want also to return the indexes of those elements in the initial two lists. How can I do so?</p>