code: def _check_required_group(self):
          
          required_group_dn = self.settings.REQUIRE_GROUP
  
          if required_group_dn is not None:
              is_member = self._get_groups().is_member_of(required_group_dn)
              if not is_member:
                  raise self.AuthenticationFailed("user is not a member of AUTH_LDAP_REQUIRE_GROUP")
  
          return True
docs: Returns True if the group requirement (AUTH_LDAP_REQUIRE_GROUP) is
          met. Always returns True if AUTH_LDAP_REQUIRE_GROUP is None.