Change an mp3's filename from [Singer] - [Song] to [Song] - [Singer] or vice versa

filename_reverser.py

import os


def reverse_filename(s):
    split_filename = s.split(" - ")
    split_filename.reverse()
    new_filename = " - ".join(split_filename)
    return new_filename

file_extension = ".mp3"

if __name__ == "__main__":
    for filename in os.listdir("."):
        if " - " in filename:
            extension_start = filename.index(file_extension)
            os.rename(filename, reverse_filename(filename[:extension_start]) + filename[extension_start:])