<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_urlfield_cache_key(model, pk, language_code=None):
 """ The low-level function to get the cache key for a model. """

    return 'anyurlfield.{0}.{1}.{2}.{3}'.format(model._meta.app_label, model.__name__, pk, language_code or get_language())