# Name: ...
# CSE 160
# Autumn 2023
# Checkin 9


class StreamingService:
    def __init__(self):
        """
        Creates a new streaming service with initially no artists or songs.
        """
        self.song_dict = {}
        # Feel free to add new fields if necessary

    def add_song(self, artist, song):
        """
        Add a song to the artist's inventory in the streaming service.
        If the artist already exists in the streaming service, add the
        song to the artist's existing catalogue of songs.

        Arguments:
            artist: a string which represents the name of the artist
            song: a string which represents the name of the song

        Returns: None.
        """

        # Your solution code goes here

    def song_inventory(self):
        """
        Return a set of tuples with the tuples in the format
        (artist_name, song_name), which represents all of the
        current artists and songs in the streaming service.
        """

        # Your solution code goes here

    def num_artists(self):
        """
        Return the number of unique artists in the streaming service.
        """

        # Your solution code goes here


s = StreamingService()
empty = StreamingService()

# Test add_song
s.add_song("WayV", "On My Youth")
assert "WayV" in s.song_dict.keys()
assert "On My Youth" in s.song_dict["WayV"]

s.add_song("WayV", "Try My Luck")
assert "WayV" in s.song_dict.keys()
assert "Try My Luck" in s.song_dict["WayV"]

s.add_song("Olivia Rodrigo", "vampire")
assert "Olivia Rodrigo" in s.song_dict.keys()
assert "vampire" in s.song_dict["Olivia Rodrigo"]

# Test song_inventory
assert s.song_inventory() == {("WayV", "On My Youth"),
                              ("WayV", "Try My Luck"),
                              ("Olivia Rodrigo", "vampire")}
assert empty.song_inventory() == set()


# Test num_artists
assert s.num_artists() == 2
assert empty.num_artists() == 0