code: def find_service_references(
          self, clazz=None, ldap_filter=None, only_one=False
      ):
          # type: (Optional[str], Optional[str], bool) -> Optional[List[ServiceReference]]
          
          return self._registry.find_service_references(
              clazz, ldap_filter, only_one
          )
docs: Finds all services references matching the given filter.
  
          :param clazz: Class implemented by the service
          :param ldap_filter: Service filter
          :param only_one: Return the first matching service reference only
          :return: A list of found reference, or None
          :raise BundleException: An error occurred looking for service
                                  references