If it was in a pet store it may not be an asian ratsnake. China imports large quantities of herps from the U.S. (probably the biggest importer of turtles from the states). They do re-export some of them so it is very possible you have a u.s. rat there. IF it is in fact a re-export and they were babies and had the ratsnake heads with no pattern then they were possibly leucistic tx rats or blizzard corns. Most babies will have a pinkish hue to them. If there was no pattern my first guess would be leucistic tx rat.