def _remove_internal_nw_nat_rules(self, ri, ports, ext_port,<EOL>intf_deleted=False):
acls = []<EOL>for port in ports:<EOL><INDENT>in_itfc_name = self._get_interface_name_from_hosting_port(port)<EOL>acls.append(self._generate_acl_num_from_port(port))<EOL>is_alone = len(port['<STR_LIT>']['<STR_LIT>']) == <NUM_LIT:1><EOL>if not intf_deleted and is_alone is True:<EOL><INDENT>self._remove_interface_nat(in_itfc_name, '<STR_LIT>')<EOL><DEDENT><DEDENT>vrf_name = self._get_vrf_name(ri)<EOL>ext_itfc_name = self._get_interface_name_from_hosting_port(ext_port)<EOL>for acl in acls:<EOL><INDENT>self._remove_dyn_nat_rule(acl, ext_itfc_name, vrf_name)<EOL><DEDENT>
Removes the NAT rules already configured when an internal network is
removed.

:param ri          -- router-info object
:param ports       -- list of affected ports where network nat rules
                      was affected
:param ext_port    -- external facing port
:param intf_deleted-- If True, indicates that the subinterface was
                      deleted.