How to use the graphistry.util.compare_versions function in graphistry

def _check_key_and_version():
        params = {'text': PyGraphistry.api_key()}
        try:
            response = requests.get(PyGraphistry._check_url(), params=params, timeout=(3,3),
                                    verify=PyGraphistry._config['certificate_validation'])
            response.raise_for_status()
            jres = response.json()

            cver = sys.modules['graphistry'].__version__
            if  'pygraphistry' in jres and 'minVersion' in jres['pygraphistry'] and 'latestVersion' in jres['pygraphistry']:
                mver = jres['pygraphistry']['minVersion']
                lver = jres['pygraphistry']['latestVersion']
                if util.compare_versions(mver, cver) > 0:
                    util.warn('Your version of PyGraphistry is no longer supported (installed=%s latest=%s). Please upgrade!' % (cver, lver))
                elif util.compare_versions(lver, cver) > 0:
                    print('A new version of PyGraphistry is available (installed=%s latest=%s).' % (cver, lver))

            if jres['success'] is not True:
                util.warn(jres['error'])
        except Exception as e:
            util.warn('Could not contact %s. Are you connected to the Internet?' % PyGraphistry._config['hostname'])