And @nutilius's knowledge of Python and executing Python scripts from KM will be best of all! Now your code is nicely formatted, hopefully they'll be back.
In the meantime, first check that your Python script is being run. A quick way to do that is to add a print command after the import statements and comment out everything below that with triple quotes (single or double, as long as they match:
import os
import sys
import datetime
import re
print("Hello World!")
'''
# --- 1. LIBRARY CHECK ---
try:
<snip>
if __name__ == "__main__":
run_chunking()
'''