title: Regex to find A and not B on a line
body: <p>I'm looking for a regex to search my python program to find all lines where <code>foo</code>, but not <code>bar</code>, is passed into a method as a keyword argument. I'm playing around with lookahead and lookbehind assertions, but not having much luck.</p>
  
  <p>Any help?</p>
  
  <p>Thanks</p>