EDNS allows for larger messages and also provides an extension mechanism for the protocol. EDNS options are typed data, and are treated much like Rdata. For example, if dnsython encouters the EDNS ECS option code when parsing a DNS wire format message, it will create a dns.edns.ECSOption object to represent it.
dns.edns.NSID
dns.edns.DAU
dns.edns.DHU
dns.edns.N3U
dns.edns.ECS
dns.edns.EXPIRE
dns.edns.COOKIE
dns.edns.KEEPALIVE
dns.edns.PADDING
dns.edns.CHAIN
dns.edns.Option
dns.edns.GenericOption
dns.edns.ECSOption
dns.edns.get_option_class
dns.edns.option_from_wire