[Development] How to print a text file from within python3?

[Kumann]

I can print from Kate but not from within a python3 script.
I tried some examples on the Internet but none work ... I always get a 'filter missing' error in the printer queue.

I assume no one knows how to print from python3.
I have the following command working in Mint Vera but will not work in Kubuntu.
The printer names are identical.

os.system('lpr -P HP_ENVY_7640_series_EEF413 ' + fpath)

I give up, going back to Mint.