How to do parallel reading from a file, Python+Linux(GNU_parallel)?

Question

linux

Good day, dear ones!
There is a primitive bash script that reads a file:
cat -v /dev/pts/2 | python3 'process.py'
Where is the python3 script:

import sys
  for string in sys.stdin:
    some_calculation(string)

My question is how can I parallelize reading and processing? To run two process.py scripts at the same time
I found GNU-parallel, but something didn't start:

cat -v /dev/pts/2 | parallel  --pipe --recstart '>' python3 process.py

How to fix it, or are there other ways to do it?
Thanks in advance!
solution found, just play around with the --block option:

cat -v /dev/pts/2 | parallel --j 3 --pipe --block 12M python3 process.py

Answer 1

solution found, just play around with the --block option:
cat -v /dev/pts/2 | parallel --j 3 --pipe --block 12M python3 process.py

Answer 2

problem in setting the task. it is not known what kind of text file we have and why it must be read in several streams.