Estoy intentando agregar un objeto Song * a una matriz Mutable y estoy perplejo ya que el recuento de la matriz no aumenta a pesar de agregar el objeto.

Song.h

#import <Foundation/Foundation.h>

@interface Song : NSObject

@property(copy, nonatomic) NSString *title, *album, *artist;
@property(copy, nonatomic) NSNumber *playTime;

@end

Song.m

#import "Song.h"

@implementation Song

@end

Playlist.h

#import <Foundation/Foundation.h>
@class Song;

@interface Playlist : NSObject

@property(copy, nonatomic) NSMutableArray *playListArray;

-(void) addSong: (Song *) tempSongToBeAdded;
-(void) removeSong: (Song *) tempSongToBeremoved;
-(void) listOfSongs;
-(NSUInteger) entries;

@end

Playlist.m

#import "Playlist.h"
#import "Song.h"

@implementation Playlist

-(void) addSong: (Song *) tempSongToBeAdded{
    NSLog(@"%s song is being added.", [tempSongToBeAdded.title UTF8String]);
    [self.playListArray addObject:tempSongToBeAdded];
}
-(void) removeSong: (Song *) tempSongToBeremoved{
    [self.playListArray removeObject:tempSongToBeremoved];
}

-(NSUInteger) entries{
    return [self.playListArray count];
}


    -(void) listOfSongs{
        NSLog(@"Hi");
        for (Song *tempSong in self.playListArray) {
            NSLog(@"title: %s", [tempSong.title UTF8String]);
        }
    }

@end

Main.m

#import <Foundation/Foundation.h>
#import "Song.h"
#import "Playlist.h"

int main(int argc, const char * argv[])
{

@autoreleasepool {

    Song *song1 = [[Song alloc] init];
    song1.title = @"Manasa";
    song1.album = @"Ye Maya Chesava";
    song1.artist = @"A. R. Rahman";
    song1.playTime = [NSNumber numberWithDouble:4.56];

    Playlist *playlist1 = [[Playlist alloc] init];

    [playlist1 addSong:song1];
    NSLog(@"The total number of songs are %lu",[playlist1 entries]);
    [playlist1 listOfSongs];




    }
return 0;
}

Recibo las entradas en la lista de reproducción como 0 y la lista de canciones como vacía. No recibo ningún error de compilación y no tengo idea de por qué los objetos no se agregan a la matriz.