def song_info(artist_name, song_title, release_date = None):       # We give no value to 'release_date'. 'None' is a placeholder
        """Build a dictionary containing information about an album."""
        song_dict = {'artist': artist_name, 'song': song_title}        # We add the two arguments provided to the dictionary
        if release_date:                                         # If there is an argument provided for 'release_date' then execute this block.
            song_dict['released'] = release_date                # Add the release date to the dictionary.
        return song_dict

    release_date = None                                          # We give the 'release_date' no value so if the user does not provide input for this variable python wont cause
                                                                 # any problems

    # Prepare the prompts.
    song_prompt = "Which song are you thinking of? "
    artist_prompt = "Who's the artist? "
    released_prompt = "When was it released? "

    while True:
        print("nEnter 'quit' at any time to stop.")

        song = input(song_prompt)
        if song == 'quit':
            break
        artist = input(artist_prompt)
        if artist == 'quit':
            break

        release_question = input("Do you know when it was released?(yes/no) ")  # Ask the use if they know the release date.
        if release_question == 'yes':                                           # If they know execute this block.
            release_date = input(released_prompt)                               # Ask the user for the release date.

            if release_date == 'quit':
                break

        elif release_question == 'quit':
            break


        song_info = song_info(artist, song, release_date)
        print(song_info)