фильтрация директории по параметрам (os.walk)

Пример из документации, вроде, это показывает:

for root, dirs, files in os.walk('python/Lib/email'):
    if 'CVS' in dirs:
        dirs.remove('CVS')  # don't visit CVS directories

Т.е. надо модифицировать dirs как текст там же и говорит:

When topdown is True, the caller can modify the dirnames list in-place
(perhaps using del or slice assignment), and walk() will only recurse into the
subdirectories whose names remain in dirnames; this can be used to prune the
search, impose a specific order of visiting, or even to inform walk() about
directories the caller creates or renames before it resumes walk() again.