title: How to append elements from 2 short lists into another big list of tuples?
body: <p>Say I have the following lists:</p>
  
  <pre><code>l1 = [('a','b','c'),('d','e','f'),('g','h','i'),('j','k','l')]
  l2 = ['x','y','z']
  l3 = ['m','n']
  </code></pre>
  
  <p>I want to extract elements from l2 and l3, then append l2[i](<code>i in range(len(l2))</code>) as the first element inside every tuple, and l3[i](<code>i in range(len(l2))</code>) as the last element inside every tuple.</p>
  
  <p>so the result will look like the followings:</p>
  
  <pre><code>l1 = [('x','a','b','c','m'),('x','a','b','c','n'),('y','a','b','c','m'),('y','a','b','c','n'), ('z','a','b','c','m'),('z','a','b','c','n')]
  </code></pre>
  
  <p>and yes, the len of l1 will be increased. </p>