code: def _check_denied_group(self):
          
          denied_group_dn = self.settings.DENY_GROUP
  
          if denied_group_dn is not None:
              is_member = self._get_groups().is_member_of(denied_group_dn)
              if is_member:
                  raise self.AuthenticationFailed(
                      "user does not satisfy AUTH_LDAP_DENY_GROUP"
                  )
  
          return True
docs: Returns True if the negative group requirement (AUTH_LDAP_DENY_GROUP)
          is met. Always returns True if AUTH_LDAP_DENY_GROUP is None.