Python 2.7.5 (default, Sep 16 2015, 17:57:16) 
[GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.53)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import re; re.compile('cr([lj])\(([^!)]*)!?([^)]*)?\)')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/kwilson/.pythonz/pythons/CPython-2.7.5/lib/python2.7/re.py", line 190, in compile
    return _compile(pattern, flags)
  File "/Users/kwilson/.pythonz/pythons/CPython-2.7.5/lib/python2.7/re.py", line 242, in _compile
    raise error, v # invalid expression
sre_constants.error: nothing to repeat
>>>