The law only refers to items sold in California, so
Coach stores in Cali wouldn't have been able to sell them, and that includes the bags discussed earlier. And when retailers there tried to sell banned items anyway, the state usually cracked down on them pretty quickly. Obviously someone from Cali can buy a bag that uses python just by going to a different state, but Coach stores can't have them in inventory. I don't know how Coach handles online or FOS orders but I'm sure there's a way the order would be blocked if the shipping address was in California.
ETA - It's not mentioned on the individual item page but the Customer Care page on the main site says "Exceptions Python cannot be shipped to California"
https://www.coach.com/shippingMethodFee.html