title: Insert Colon between each element of a list python
body: <pre><code>[x[1] for x in matches]
  x
  newtest = [x2[-2:] for x2 in x]
  newtest
  </code></pre>
  
  <p>I have a list </p>
  
  <pre><code>[u'asvbsMasd', u'abdhesMrty', u'ahdksC', u'ahdeO', u'ahdnL', u'ahddsS',]
  </code></pre>
  
  <p>now i want my list to be like a colon between where it finds a lower case and upper case </p>
  
  <pre><code>[u'asvbs:Masd', u'abdhes:Mrty', u'ahdks:C', u'ahde:Oqqq', u'ahdn:L', u'ahdds:S',]
  </code></pre>