title: Python: How to get every combination in list
body: <p>I have a large amount of lists of lists. Here are only a few: </p>
  
  <pre><code>L1=(['G', 'C', 'A'], ['T', 'C'], ['T', 'C'])
  L2=(['T', 'C'], ['T', 'C'], ['T', 'C'])
  </code></pre>
  
  <p>I need to get lists like this: (So basically every repeat from list to list)</p>
  
  <pre><code>L1=['GTT','CTT','ATT','GCC','CCC','ACC','GTC','CTC','ATC','GCT','CCT','ACT']
  L2=['TTT','CTT','TCC','CCC','TCT','CTC','TTC','CCT']
  </code></pre>