Traceback (most recent call last):
  File "<pyshell#124>", line 1, in <module>
    re.match(r'(\d+)([+-*])(\d+)',a).groups()
  File "C:\Python33\Lib\re.py", line 156, in match
    return _compile(pattern, flags).match(string)
  File "C:\Python33\Lib\re.py", line 281, in _compile
    p = sre_compile.compile(pattern, flags)
  File "C:\Python33\Lib\sre_compile.py", line 494, in compile
    p = sre_parse.parse(p, flags)
  File "C:\Python33\Lib\sre_parse.py", line 748, in parse
    p = _parse_sub(source, pattern, 0)
  File "C:\Python33\Lib\sre_parse.py", line 360, in _parse_sub
    itemsappend(_parse(source, state))
  File "C:\Python33\Lib\sre_parse.py", line 696, in _parse
    p = _parse_sub(source, state)
  File "C:\Python33\Lib\sre_parse.py", line 360, in _parse_sub
    itemsappend(_parse(source, state))
  File "C:\Python33\Lib\sre_parse.py", line 506, in _parse
    raise error("bad character range")
sre_constants.error: bad character range