# Receive notification of a notation declaration event.
	#
	# It is up to the application to record the notation for later
	# reference, if necessary;
	# notations may appear as attribute values and in unparsed entity
	# declarations, and are sometime used with processing instruction
	# target names.
	#
	# At least one of `public_id` and `system_id` must be non-null.
	# If a system identifier is present, and it is a URL, the SAX
	# parser must resolve it fully before passing it to the
	# application through this event.
	#
	# There is no guarantee that the notation declaration will be
	# reported before any unparsed entities that use it.
	#
	# Parameters:
	#
	# * `name`: notation name.
	# * `public_id`: notation's public identifier, or null if none was given.
	# * `system_id`: notation's system identifier, or null if none was given.
	#
	# SEE: `sax::Attributes`
	fun notation_decl(name: String, public_id: String, system_id: String) do end