pyPDF2: Merge 2 PDF pages into one side by side

merge_pdfs.py

import sys
from pathlib import Path
from itertools import zip_longest
from PyPDF2 import PdfWriter, PdfReader, PageObject

def merge_two_into_one(in_path, out_path, force=False):
    in_path = Path(in_path)
    out_dir = Path(out_dir)
    writer = PdfWriter()
    reader = PdfReader(in_path)

    def grouper(iterable, n, fillvalue=None):
        args = [iter(iterable)] * n
        return zip_longest(*args, fillvalue=fillvalue)

    for i, (page1, page2) in enumerate(grouper(reader.pages, n=2)):
        merged = PageObject.createBlankPage(None,
                                            2*page1.mediaBox.getWidth(),
                                            page1.mediaBox.getHeight())
        merged.mergePage(page1)
        if page2 is not None:
            merged.mergeScaledTranslatedPage(page2, 1, page1.mediaBox.getWidth(), 0)
        writer.addPage(merged)

    with open(out_path, "wb") as out_file:
        writer.write(out_file)