How to run a Python script on all 4 Raspberry cores?

Question

Raspberry Pi

Good afternoon, there is a Python script, the script processes pictures using the open cv library.
The algorithm is as follows: we read the picture, run the transformations, write the result.
During the conversion (when the picture is already in RAM), the processor is loaded by 30%, I want to speed up the process, how to load the processor by 100%
Increase the priority? Run on all 4 cores?