Most likely the shipper will need to get a Cities permit to send you a snake if it is on a Cities list. If it isn't listed then they don't need a permit to ship it. However not everybody who ships to Canada will bother getting a permit which means you risk the animal being stopped at the border.

Personally I will just find a Canadian breeder for the snakes you want to get. Its cheaper in the long run.
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PHLdyPayne