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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _remove_internal_nw_nat_rules(self, ri, ports, ext_port, intf_deleted=False):
 """ 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. """

        acls = []
        # first disable nat in all inner ports
        for port in ports:
            in_itfc_name = self._get_interface_name_from_hosting_port(port)
            acls.append(self._generate_acl_num_from_port(port))
            is_alone = len(port['change_details']['current_ports']) == 1
            if not intf_deleted and is_alone is True:
                self._remove_interface_nat(in_itfc_name, 'inside')
        # There is a possibility that the dynamic NAT rule cannot be removed
        # from the running config, if there is still traffic in the inner
        # interface causing a rule to be present in the NAT translation
        # table. For this we give 2 seconds for the 'inside NAT rule' to
        # expire and then clear the NAT translation table manually. This can
        # be costly and hence is not enabled here, pending further
        # sinvestigation.

        # LOG.debug("Sleep for 2 seconds before clearing NAT rules")
        # time.sleep(2)
        # clear the NAT translation table
        # self._remove_dyn_nat_translations()

        # remove dynamic nat rules and acls
        vrf_name = self._get_vrf_name(ri)
        ext_itfc_name = self._get_interface_name_from_hosting_port(ext_port)
        for acl in acls:
            self._remove_dyn_nat_rule(acl, ext_itfc_name, vrf_name)