Incompatible Types: song is not a string and will not work with prompt action.

package com.teamtreehouse;

import com.teamtreehouse.model.Song;
import com.teamtreehouse.model.SongBook;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Map;


public class KaraokeMachine {
    private SongBook mSongBook;
    private BufferedReader mReader;
    private Map<String, String> mMenu;

    public KaraokeMachine(SongBook songBook) {
        mSongBook = songBook;
        mReader = new BufferedReader(new InputStreamReader(System.in));
        mMenu = new HashMap<String, String>();
        mMenu.put("add", "Add a new song to the song book");
        mMenu.put("quit", "Give up.  Exit the program");
    }

    private String promtAction() {
    System.out.printf("There are %d songs available. Your options are:  %n",
                                     mSongBook.getSongCount()); 
                for (Map.Entry<String, String> option : mMenu.entrySet()) {
                System.out.printf("%s - %s %n",
                                                 option.getKey(),
                                                 option.getValue());    
                }
                System.out.print("What do you want to do:  ");
                String choice = mReader.readLine();
                return choice.trim().toLowerCase();
}
  public void run() {
    String choice = ""; 
        do {
            try {
            choice = promtAction();
                switch(choice) {
                case "add":
                Song song = promtAction();
                mSongBook.addSong(song);
                System.out.printf("%s added! %n%n", song);
                break;
                case "quit": 
                System.out.println("Thanks for playing!");
                break;
                default:
                System.out.printf("Unknown choice:  '%s'. Try again. %n%n%n",
                                                 choice);
            }
            } catch(IOException ioe) {
                System.out.println("Problem with input");
                ioe.printStackTrace();
            }
        }while (!choice.equals("quit"));
        }
        private Song promptNewSong() {
            System.out.print("Enter the artist's name:  ");
            String artist = mReader.readLine();
            System.out.print("Enter the Title: ");
            String title = mReader.readLine();
            System.out.print("Enter the video URL:  ");
            String videoUrl = mReader.readLine();
            return new Song(artist, title, videoUrl);
        }
    }