code: def _flow_check_handler_internal(self):
          
          integ_flow = self.integ_br_obj.dump_flows_for(
              in_port=self.int_peer_port_num)
          ext_flow = self.ext_br_obj.dump_flows_for(
              in_port=self.phy_peer_port_num)
          for net_uuid, lvm in six.iteritems(self.local_vlan_map):
              vdp_vlan = lvm.any_consistent_vlan()
              flow_required = False
              if not (vdp_vlan and ovs_lib.is_valid_vlan_tag(vdp_vlan)):
                  return
              if not self._check_bridge_flow(integ_flow, vdp_vlan, lvm.lvid):
                  LOG.error("Flow for VDP Vlan %(vdp_vlan)s, Local vlan "
                            "%(lvid)s not present on Integ bridge",
                            {'vdp_vlan': vdp_vlan, 'lvid': lvm.lvid})
                  flow_required = True
              if not self._check_bridge_flow(ext_flow, lvm.lvid, vdp_vlan):
                  LOG.error("Flow for VDP Vlan %(vdp_vlan)s, Local vlan "
                            "%(lvid)s not present on External bridge",
                            {'vdp_vlan': vdp_vlan, 'lvid': lvm.lvid})
                  flow_required = True
              if flow_required:
                  LOG.info("Programming flows for lvid %(lvid)s vdp vlan"
                           " %(vdp)s",
                           {'lvid': lvm.lvid, 'vdp': vdp_vlan})
                  self.program_vm_ovs_flows(lvm.lvid, 0, vdp_vlan)
docs: Periodic handler to check if installed flows are present.
  
          This handler runs periodically to check if installed flows are present.
          This function cannot detect and delete the stale flows, if present.
          It requires more complexity to delete stale flows. Generally, stale
          flows are not present. So, that logic is not put here.