python 2.7相当于内置方法int.from_bytes

I'm trying to make my project python2.7 and 3 compatible and python 3 has the built in method int.from_bytes. Does the equivalent exist in python 2.7 or rather what would be the best way to make this code 2.7 and 3 compatible?I'm trying to make my project python2.7 and 3 c