title: Multiple occurences of same character in a string regexp - Python
body: <p>Given a string made up of 3 capital letters, 1 small caps and another 3 capital ones,
  e.g. AAAaAAA</p>
  
  <p>I can't seem to find a regexp that would find a string which matches a string that has:</p>
  
  <ul>
  <li>first 3 capital letters all different</li>
  <li>any small caps letter</li>
  <li>first 2 same capital letters as the very first one</li>
  <li>last capital letter the same as the last capital letter in the first "trio"</li>
  </ul>
  
  <p>e.g. <strong>A</strong> B <em>C</em> a <strong>AA</strong> <em>C</em> (no spaces)</p>
  
  <p>EDIT:</p>
  
  <p>Turns out I needed something slightly different e.g. ABCaAAC where 'a' is the
  small caps version of the very fist character, not just any character</p>