code: def get_ipv4fs_table(self):
          
          ipv4fs_table = self._global_tables.get(RF_IPv4_FLOWSPEC)
          # Lazy initialization of the table.
          if not ipv4fs_table:
              ipv4fs_table = IPv4FlowSpecTable(self._core_service,
                                               self._signal_bus)
              self._global_tables[RF_IPv4_FLOWSPEC] = ipv4fs_table
              self._tables[(None, RF_IPv4_FLOWSPEC)] = ipv4fs_table
  
          return ipv4fs_table
docs: Returns global IPv4 Flow Specification table.
  
          Creates the table if it does not exist.