OFFENCES WITHIN CANADA
4. Interpretation -- customary international law
(4) For greater certainty, crimes described in Articles 6 and 7 and paragraph 2 of
Article 8 of the Rome Statute are, as of July 17, 1998, crimes according to customary
international law. This does not limit or prejudice in any way the application of existing
or developing rules of international law.
Relationship between Rome Statute and existing or developing rules of international law
EDIT.