PyPDF2 append_function can't find file - python-3.x

Question

I want to use the PyPDF2 module to merge PDFs.
The following code works fine:
import PyPDF2
import sys
import os
input_path = r'\Users\XXXXX\OneDrive\Desktop\PDF_File_Input'
merger = PyPDF2.PdfFileMerger()
for file in os.listdir(input_path):
if file.endswith(".pdf"):
print(file)
As soon as I implement the append function I'm getting a traceback error from line 10. FileNotFoundError: [Errno 2] No such file or directory: 'abc.pdf'
import PyPDF2
import sys
import os
input_path = r'\Users\XXXXX\OneDrive\Desktop\PDF_File_Input'
merger = PyPDF2.PdfFileMerger()
for file in os.listdir(input_path):
if file.endswith(".pdf"):
merger.append(file)
merger.write("combined_file.pdf")
I don't understand why the file can be found via print but not by the append function.

Answer 1

If the path is correct, then most likely has something to do with the way you implement the Merger.
def run_mergepdf(args):
check_required(args, ["input", "output"])
print("Number of input files: {0}".format(len(args.input)))
#Preliminary checks
print("Checking read/write status")
check_files(args.input, action="r")
check_files([args.output], action="w")
#Join pdfs
print("Starting to merge PDFs")
merger = PdfFileMerger(strict=False)
for pdf in args.input:
if os.stat(pdf).st_size != 0:
merger.append(PdfFileReader(pdf))
print("Writing merged file: {0}".format(args.output))
merger.write(args.output)
print("PDFs merged successfully!")