def coerce(cls, string):
        """Create a :class:`Requirement` object from a given package spec."""
        match = re.match(cls.spec_regex, string)
        if not match:
            raise InvalidRequirementSpecError("could not parse requirement")
        package = match.group(1)
        if all(match.group(2, 3)):
            version = "".join(match.group(2, 3))
        else:
            version = None
        return cls(package, version)
def reverse(self, request, view_name):
        """
        Returns the URL of this tenant.
        """
        http_type = 'https://' if request.is_secure() else 'http://'

        domain = get_current_site(request).domain

        url = ''.join((http_type, self.schema_name, '.', domain, reverse(view_name)))

        return url