While trying to print data using po data it says
error: use of undeclared identifier 'data'
error: 1 errors parsing expression
-(void)viewWillAppear:(BOOL)animated {
    NSMutableURLRequest*req=[[NSMutableURLRequest alloc]init];
    NSURL*url=[NSURL URLWithString:@"http://www.thomas-bayer.com/sqlrest/CUSTOMER/"];
    [req setURL:url];
    [[[NSURLSession sharedSession]dataTaskWithRequest:req completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
        if(error){
            NSLog(@"error");
        }else{}
    }] resume];
}
 
     
     
     
    