def _import_next_layer(self, proto, length=None, *, version=<NUM_LIT:4>, extension=False):
if length == <NUM_LIT:0>:<EOL><INDENT>from pcapkit.protocols.null import NoPayload as Protocol<EOL><DEDENT>elif self._sigterm or proto == <NUM_LIT>:<EOL><INDENT>from pcapkit.protocols.raw import Raw as Protocol<EOL><DEDENT>elif proto == <NUM_LIT>:<EOL><INDENT>from pcapkit.protocols.internet.ah import AH as Protocol<EOL><DEDENT>elif proto == <NUM_LIT>:<EOL><INDENT>from pcapkit.protocols.internet.hip import HIP as Protocol<EOL><DEDENT>elif proto == <NUM_LIT:0>:<EOL><INDENT>from pcapkit.protocols.internet.hopopt import HOPOPT as Protocol<EOL><DEDENT>elif proto == <NUM_LIT>:<EOL><INDENT>from pcapkit.protocols.internet.ipv6_frag import IPv6_Frag as Protocol<EOL><DEDENT>elif proto == <NUM_LIT>:<EOL><INDENT>from pcapkit.protocols.internet.ipv6_opts import IPv6_Opts as Protocol<EOL><DEDENT>elif proto == <NUM_LIT>:<EOL><INDENT>from pcapkit.protocols.internet.ipv6_route import IPv6_Route as Protocol<EOL><DEDENT>elif proto == <NUM_LIT>:<EOL><INDENT>from pcapkit.protocols.internet.mh import MH as Protocol<EOL><DEDENT>elif proto == <NUM_LIT:4>:<EOL><INDENT>from pcapkit.protocols.internet.ipv4 import IPv4 as Protocol<EOL><DEDENT>elif proto == <NUM_LIT>:<EOL><INDENT>from pcapkit.protocols.internet.ipv6 import IPv6 as Protocol<EOL><DEDENT>elif proto == <NUM_LIT:6>:<EOL><INDENT>from pcapkit.protocols.transport.tcp import TCP as Protocol<EOL><DEDENT>elif proto == <NUM_LIT>:<EOL><INDENT>from pcapkit.protocols.transport.udp import UDP as Protocol<EOL><DEDENT>else:<EOL><INDENT>from pcapkit.protocols.raw import Raw as Protocol<EOL><DEDENT>next_ = Protocol(self._file, length, version=version, extension=extension,<EOL>error=self._onerror, layer=self._exlayer, protocol=self._exproto)<EOL>return next_<EOL>
Import next layer extractor.

        Positional arguments:
            * proto -- str, next layer protocol name
            * length -- int, valid (not padding) length

        Keyword Arguments:
            * version -- int, IP version (4 in default)
                            <keyword> 4 / 6
            * extension -- bool, if is extension header (False in default)
                            <keyword> True / False

        Returns:
            * bool -- flag if extraction of next layer succeeded
            * Info -- info of next layer
            * ProtoChain -- protocol chain of next layer
            * str -- alias of next layer

        Protocols:
            * IPv4 -- internet layer
            * IPv6 -- internet layer
            * AH -- internet layer
            * TCP -- transport layer
            * UDP -- transport layer