Some versions of python do not tolerate this regex:
r'(\w*)?'
ERROR: test_incr (__main__.TestCommands)
----------------------------------------------------------------------
Traceback (most recent call last):
File "tests/memcached/test_memcached.py", line 464, in test_incr
self.assertRegexpMatches(call('incr key 1\r\n').decode(), r'0(\w*)?\r\n')
File "/usr/lib64/python3.3/unittest/case.py", line 1178, in deprecated_func
return original_func(*args, **kwargs)
File "/usr/lib64/python3.3/unittest/case.py", line 1153, in assertRegex
expected_regex = re.compile(expected_regex)
File "/usr/lib64/python3.3/re.py", line 214, in compile
return _compile(pattern, flags)
File "/usr/lib64/python3.3/re.py", line 281, in _compile
p = sre_compile.compile(pattern, flags)
File "/usr/lib64/python3.3/sre_compile.py", line 498, in compile
code = _code(p, flags)
File "/usr/lib64/python3.3/sre_compile.py", line 483, in _code
_compile(code, p.data, flags)
File "/usr/lib64/python3.3/sre_compile.py", line 75, in _compile
elif _simple(av) and op is not REPEAT:
File "/usr/lib64/python3.3/sre_compile.py", line 362, in _simple
raise error("nothing to repeat")
sre_constants.error: nothing to repeat
ca85016556