If installed version conflicts with required version

def is_conflicting(self):
        """If installed version conflicts with required version"""
        # unknown installed version is also considered conflicting
        if self.installed_version == self.UNKNOWN_VERSION:
            return True
        ver_spec = (self.version_spec if self.version_spec else '')
        req_version_str = '{0}{1}'.format(self.project_name, ver_spec)
        req_obj = pkg_resources.Requirement.parse(req_version_str)
        return self.installed_version not in req_obj