title: how do I include a boolean AND within a regex?
body: <p>Is there a way to get single regex to satisfy this condition??</p>
  
  <p>I am looking for a "word" that has three letters from the set MBIPI, any order, 
  but MUST contain an I.</p>
  
  <p>ie.</p>
  
  <p>re.match("[MBDPI]{3}", foo) and "I" in foo</p>
  
  <p>So this is the correct result (in python using the re module), but can I get this from a single regex? </p>
  
  <pre><code>&gt;&gt;&gt; for foo in ("MBI", "MIB", "BIM", "BMI", "IBM", "IMB", "MBD"):
  ...     print foo,
  ...     print re.match("[MBDPI]{3}", foo) and "I" in foo
  MBI True
  MIB True
  BIM True
  BMI True
  IBM True
  IMB True
  MBD False
  </code></pre>
  
  <p>with regex I know I can use | as a boolean OR operator, but is there a boolean AND equivalent?</p>
  
  <p>or maybe I need some forward or backward lookup?</p>