[issue2551042] Regular expression error on python3.7

New submission from Sergi Almacellas Abellana:

I've cloned latest trunk, installed using python setup.py install 
and executed: 

$ roundup-admin -i test install jinja2

Which have me the following exception:

Traceback (most recent call last):
  File "/home/pokoli/.virtualenvs/roundup/lib/python3.7/sre_parse.py",
line 1021, in parse_template
    this = chr(ESCAPES[this][1])
KeyError: '\\w'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/pokoli/.virtualenvs/roundup/bin/roundup-admin", line 2, in
<module>
    from roundup.scripts.roundup_admin import run
  File
"/home/pokoli/.virtualenvs/roundup/lib/python3.7/site-packages/roundup/scripts/roundup_admin.py",
line 40, in <module>
    from roundup.admin import AdminTool
  File
"/home/pokoli/.virtualenvs/roundup/lib/python3.7/site-packages/roundup/admin.py",
line 30, in <module>
    import roundup.instance
  File
"/home/pokoli/.virtualenvs/roundup/lib/python3.7/site-packages/roundup/instance.py",
line 43, in <module>
    from roundup.cgi import client, templating
  File
"/home/pokoli/.virtualenvs/roundup/lib/python3.7/site-packages/roundup/cgi/client.py",
line 38, in <module>
    from roundup import rest
  File
"/home/pokoli/.virtualenvs/roundup/lib/python3.7/site-packages/roundup/rest.py",
line 326, in <module>
    class RestfulInstance(object):
  File
"/home/pokoli/.virtualenvs/roundup/lib/python3.7/site-packages/roundup/rest.py",
line 587, in RestfulInstance
    @Routing.route("/data/<:class_name>", 'GET')
  File
"/home/pokoli/.virtualenvs/roundup/lib/python3.7/site-packages/roundup/rest.py",
line 279, in route
    rule = re.compile(cls.__var_to_regex.sub(cls.url_to_regex, rule))
  File "/home/pokoli/.virtualenvs/roundup/lib/python3.7/re.py", line
309, in _subx
    template = _compile_repl(template, pattern)
  File "/home/pokoli/.virtualenvs/roundup/lib/python3.7/re.py", line
300, in _compile_repl
    return sre_parse.parse_template(repl, pattern)
  File "/home/pokoli/.virtualenvs/roundup/lib/python3.7/sre_parse.py",
line 1024, in parse_template
    raise s.error('bad escape %s' % this, len(this))
re.error: bad escape \w at position 2

----------
messages: 6463
nosy: pokoli
severity: normal
status: new
title: Regular expression error on python3.7
type: crash
versions: devel

_________________________________________________
Roundup tracker <[email protected]>
<https://issues.roundup-tracker.org/issue2551042>
_________________________________________________