This is a simple tool to merge scanned PDFs if you have scanner with a document feeder but that doesn't support double sided pages.
The idea is to scan the document stack into two PDFs, a forward one of the front of the pages and a backward one with the back of the pages. Then this script can be used to merge the two into a coherent single PDF with the pages in order.
It is recommended to install this from PyPi:
pip install scan-merge