cython runtime error on Linux (CentOS) python2.7 build

[wesbarris]

I have built cython like this:

cd /usr/local/src/python/Cython-0.25.2
/usr/local/bin/python2.7 setup.py build
sudo /usr/local/bin/python2.7 setup.py install --prefix=/usr/local | tee >junk.log

I received no errors during the install process.

When I try to run cython, I get this runtime error:

user@myhost> cython
Traceback (most recent call last):
File "/usr/local/bin/cython", line 11, in
load_entry_point('Cython==0.25.2', 'console_scripts', 'cython')()
File "/usr/local/lib/python2.7/site-packages/pkg_resources/init.py", line 560, in load_entry_point
return get_distribution(dist).load_entry_point(group, name)
File "/usr/local/lib/python2.7/site-packages/pkg_resources/init.py", line 2648, in load_entry_point
return ep.load()
File "/usr/local/lib/python2.7/site-packages/pkg_resources/init.py", line 2302, in load
return self.resolve()
File "/usr/local/lib/python2.7/site-packages/pkg_resources/init.py", line 2308, in resolve
module = import(self.module_name, fromlist=['name'], level=0)
File "/usr/local/lib/python2.7/site-packages/Cython-0.25.2-py2.7-linux-x86_64.egg/Cython/Compiler/Main.py", line 30, in
from .Symtab import ModuleScope
File "/usr/local/lib/python2.7/site-packages/Cython-0.25.2-py2.7-linux-x86_64.egg/Cython/Compiler/Symtab.py", line 18, in
from . import PyrexTypes
File "/usr/local/lib/python2.7/site-packages/Cython-0.25.2-py2.7-linux-x86_64.egg/Cython/Compiler/PyrexTypes.py", line 17, in
from .Code import UtilityCode, LazyUtilityCode, TempitaUtilityCode
File "Cython/Compiler/Code.py", line 838, in init Cython.Compiler.Code (/usr/local/src/python/Cython-0.25.2/Cython/Compiler/Code.c:81208)
possible_unicode_identifier = re.compile(br"(?![0-9])\w+$".decode('ascii'), re.U).match
File "/usr/local/lib/python2.7/re.py", line 194, in compile
return _compile(pattern, flags)
File "/usr/local/lib/python2.7/re.py", line 251, in _compile
raise error, v # invalid expression
sre_constants.error: unexpected end of regular expression

I am not a python (or cython) user. I'm just trying to get it installed for my users. What does the above error suggest?