class Playlist:
    def __init__(self):
        self._tracks = []

    def add(self, track):
        self._tracks.append(track)

    def __len__(self) -> int:
        # Retorna el número de canciones en la playlist
        return len(self._tracks)

    def __getitem__(self, index) -> str:
        # Permite acceder a una canción por índice
        return self._tracks[index]


def playlist_ops(songs):
    pl = Playlist()
    for song in songs:
        pl.add(song)
    return {"length": len(pl), "first": pl[0], "last": pl[-1]}