Python Off Set Patcher

I am trying to replace the binary data in a certain file with alternative binary data I have by injecting them at certain offsets of this file...is there a way I can achieve this with a python script if so can you show me a patch that I can reference to do this. Some method similar to Dup2/diablo2oo2's Universal Patcher that does offset and seek and replace patching...except it crashes with large files, so I thought a python script is way to go.