serializers.py

class Song(object):
    title = ''
    artist = ''
    album = ''
    id = ''

    def __init__(self, title, artist, album, id):
        self.title = title
        self.artist = artist
        self.album = album
        self.id = id

    def __repr__(self):
        return f"Song<{self.title} - {self.artist}>"

    @staticmethod
    def from_spotify(json):
        return Song(
            title=json['name'],
            artist=json['artists'][0]['name'],  # Just take the first artist
            album=json['album']['name'],
            id=json['id'],
        )

    @staticmethod
    def from_gpm(json):
        return Song(
            title=json['title'],
            artist=json['artist'],
            album=json['album'],
            id=json.get('storeId'),  # This isn't always present
        )


class Playlist(object):
    songs = []
    title = ''
    description = ''
    id = ''

    def __init__(self, songs, title, description, id):
        self.songs = songs
        self.title = title
        self.description = description
        self.id = id

    def __repr__(self):
        return f"Playlist<{self.title}>"

    @staticmethod
    def from_spotify(json):
        return Playlist(
            songs=[Song.from_spotify(item['track']) for item in json['tracks']['items']],
            title=json['name'],
            description=json['description'],
            id=json['id'],
        )

    @staticmethod
    def from_gpm(json):
        return Playlist(
            songs=[Song.from_gpm(item['track']) for item in json['tracks']],
            title=json['name'],
            description=json['description'],
            id=json['id'],
        )