Write a python Playlist and Song classes for the test cases.

def test_PlaylistSong_classes(): song1 = Song("spotify1", 20) assert((song1.title == "spotify1") and (song1.rating == 20))

song2 = Song("spotify2") assert((song2.title == "spotify2") and (song2.rating == 16))

playlist1 = Playlist([song1, song2]) assert(playlist1.songs == [song1, song2]) assert(playlist1.average_rating() == 18) #average of 20 and 16

playlist2 = Playlist([song1]) assert(playlist2.songs == [song1]) assert(playlist2.average_rating() == 20) #average of 20

playlist2.add_song(song2)# add_song assert(playlist2.songs == [song1, song2]) assert(playlist2.average_rating() == 18) # average of 20 and 16 print("done!")