How to learn about print options keys from pycups?

Question

Via trial and error and looking into the ppd I wrote script below that allows you to print on different trays. I found the correct names for value and key of the job-options in the ppd.

Just by looking into conn.getPrinterAttributes(printer)['media-source-supported'] those options do not became clear.

I feel like there must be a way how you can get all the possible job options in a better fashion than just looking them up in the ppd file, but I fail to find any documentation on this problem and because the underlying base is in C, I am also a bit unsure how the connection between python and C works there.

In order to better understand how to use pycups and maybe also how the connection between python and C works here, I decided to ask on stackoverflow.

I have ...

Following pycups

Followed pip show pycups but only found the cupshelpers and pycups info i.e.

This is a set of Python bindings for the libcups library from CUPS project.

But I didn't find the exact bindings only:

cups.cpython-310-x86_64-linux-gnu.so
cupsext.cpython-310-x86_64-linux-gnu.so
cupshelpers/
cupshelpers-1.0-py3.10.egg-info
pycups-2.0.1.egg-info

Program for reference

#!/usr/bin/env python3
import cups

def list_printers():
    conn = cups.Connection()
    printers = conn.getPrinters()

    print("Available printers:")
    for printer in printers:
        print(f"Printer: {printer}")
        print("Supported options:")
        options = conn.getPrinterAttributes(printer)['media-source-supported']
        for option in options:
            cleaned_option = ''.join(c for c in option if c.isalnum()).upper()
            print(f"  {cleaned_option}")
        print()


def print_document(printer_name, document_path, tray_option):
    conn = cups.Connection()
    printers = conn.getPrinters()

    if printer_name not in printers:
        print(f"Printer '{printer_name}' not found.")
        return

    job_options = {
        'InputSlot': tray_option,
    }
    print(job_options)

    with open(document_path, 'rb') as document:
        print_job_id = conn.printFile(printer_name, document_path, "Print Job", job_options)
        print(f"Document '{document_path}' sent to '{printer_name}' with Job ID: {print_job_id}")

if __name__ == "__main__":
    # Specify the printer name, document paths, and tray options
    printer_name = "Kyocera-ECOSYS-P3055dn-KPDL"

    document1_path = "Tray1.pdf"
    document2_path = "Tray2.pdf"

    options = ["PF430A", "PF430B"]

    for option in options:
        print_document(printer_name, f"{option}.pdf", option)