pep8 coding style

import os,sys

import os

import sys

import numpy as np

from astropy.io import fits

PRESCAN_Y, IMAGE_Y, OVERSCAN_Y = 0, 4616, 84

BLOCK_WIDTH = PRESCAN_X + IMAGE_X + OVERSCAN_X

def process_single_file(filename):

    with fits.open(filename) as hdul:

        data = hdul[1].data

    fits.writeto(output_path, blocks_final, overwrite=True)

    print(f"OK:{output_path}")

if __name__ == "__main__":

    if len(sys.argv) > 1:

        fn = sys.argv[1]