melophonic

#import "APIManager.h"

@implementation APIManager

+ (instancetype)shared {
    static APIManager *sharedManager = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        sharedManager = [[self alloc] init];
    });

melophonic

// APIManager.h

#import <Foundation/Foundation.h>

@interface APIManager : NSObject

+ (instancetype) shared;

@end

melophonic

sudo rm /var/lib/apt/lists/lock
sudo rm /var/lib/dpkg/lock
sudo rm /var/cache/apt/archives/lock