CR_RE = re.compile('cr([lj])\(([^!)]*)!?([^)]*)?\)')
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/re.py", line 190, in compile
    return _compile(pattern, flags)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/re.py", line 242, in _compile
    raise error, v # invalid expression

Exception message: nothing to repeat