/**
 * Write a description of interface PlayList here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */

public interface PlayList
{
    /**
     * Adds new song to playlist. Every 
     * song can be in the playlist only once
     * @param song song to be added
     * @returns true if the song was successfully added
     * false otherwise
     */
    boolean addSong(Song song);
    /**
     * Simulates playing songs in the playlist.
     * Writes out the info about the songs.
     * @throws EmptyPlayListException when the 
     * playlist is empty.
     */
    void playSongs() throws EmptyPlayListException;
    
    /**
     * Removes song from the playlist.
     * @return song that has been removed.
     * @throws NoSuchSongException if the playlist
     * does not contain the song.
     */
    Song removeSong(Song song) throws NoSuchSongException;
}