docs: def _set_client(self):
          """Set client property if not set."""
          if self._client is None:
              if mongo_proxy:
                  self._client = mongo_proxy.MongoProxy(
                      pymongo.MongoClient(self.connection_string),
                      logger=LOG)
              else:
                  LOG.warning("MongoDBProxy not imported. AutoReconnect "
                              "is not enabled.")
                  self._client = mongo_proxy.MongoProxy(
                      pymongo.MongoClient(self.connection_string),
                      logger=LOG)
              LOG.debug("Created new connection to MongoDB: %s",
                        self.safe_connection_string)