api for generating filehistory in 6.x

System

I'm working on migrating an teamsite based application from 5.5.2 to 6.x. The person who has worked on that needs me to implement a capability for storing file history in the backing store since we do not use editions. He sent
me some code/pseudo code for doign thsi from the 5.5.3 era, and I am to use this to find the wway to do this in 6.0. The pseudo code is below and would appreciate any pointers to the new API in 6:
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