@cached_property<EOL><INDENT>def icmpv4(self):<DEDENT>
ipproto, proto_start = self.protocol<EOL>if ipproto == Protocol.ICMP:<EOL><INDENT>return ICMPv4Header(self, proto_start)<EOL><DEDENT>
- An ICMPv4Header instance, if the packet is valid ICMPv4.
- None, otherwise.