'Clean up urlpattern regexes into something readable by humans:
From:
> "^(?P<sport_slug>\w+)/athletes/(?P<athlete_slug>\w+)/$"
To:
> "{sport_slug}/athletes/{athlete_slug}/"'

def _simplify(self, pattern):

    result = self._optional_group_matcher.sub((lambda m: ('%s' % m.group(1))), pattern)
    result = self._named_group_matcher.sub((lambda m: ('{%s}' % m.group(1))), result)
    result = self._non_named_group_matcher.sub('{var}', result)
    result = self._either_option_matcher.sub((lambda m: m.group(1)), result)
    result = result.replace('^', '').replace('$', '').replace('?', '').replace('//', '/').replace('\\', '')
    return result
