docs: def CountFlowLogEntries(self, client_id, flow_id, cursor=None):
      """Returns number of flow log entries of a given flow."""
  
      query = ("SELECT COUNT(*) "
               "FROM flow_log_entries "
               "FORCE INDEX (flow_log_entries_by_flow) "
               "WHERE client_id = %s AND flow_id = %s ")
      args = [db_utils.ClientIDToInt(client_id), db_utils.FlowIDToInt(flow_id)]
  
      cursor.execute(query, args)
      return cursor.fetchone()[0]