File Name Split on Dashes

Hay guys. I'm developing an MP3 player of sorts in Python, and I've devised a way to split a file name by dashes, and return the artist and track separately, but I'm struggling with returning something if no dash is found. In that case, I'd like to return the original file name, and an empty string. As it is now, if no dash is found in a file name, it will just return "None".

Here is my function:

def parseName(song):
    flags = chr(6), chr(45), chr(173), chr(8211)
    for flag in flags:
        for letter in song:
            if flag == letter:
                        return song.split(flag)

Could anyone help? I'd appreciate it.