!/usr/bin/env python3 import sys import argparse parser = argparse.ArgumentParser(description=‘Check for missing whitespace on specific lines.’) parser.add_argument(‘tutorial’, type=argparse.FileType(‘r’)) parser.add_argument(‘–fix’, action=‘store_true’) args = parser.parse_args()

def lint(fh):

in_diff = False
min_length = sys.maxsize
failures = 0
fixed = []
for lineno, line in enumerate(fh.readlines()):
    line = line.rstrip('\n')
    if '```diff' in line:
        in_diff = True
        min_length = line.index('`') + 1
    elif in_diff and '```' in line:
        in_diff = False
        min_length = sys.maxsize
    elif in_diff and len(line) < min_length:
        print(f'{fh.name}: {lineno}: diff line too short ({len(line)} < {min_length})!: "{line}"')
        line += " " * (min_length - len(line))
        failures += 1
    fixed.append(line)
return failures, fixed

if __name__ == ‘__main__’:

failures, fixed = lint(args.tutorial)
if args.fix:
    with open(args.tutorial.name, 'w') as handle:
        handle.write("\n".join(fixed))
if failures:
    print(f'ERROR: Linting diffs failed with {failures} failures')
print('All diffs OK!')