code: def get_subdomain_iterator(self, domain, limit=None, offset=None):
          
          return SubdomainResultsIterator(self._manager, domain=domain)
docs: Returns an iterator that will return each available subdomain for the
          specified domain. If there are more than the limit of 100 subdomains,
          the iterator will continue to fetch subdomains from the API until all
          subdomains have been returned.