NSDate *date = [NSDate date];
Person *cosmo = [[Person alloc] initWithFirst:@"Cosmo" last:@"Kramer" birthdate:date];
Person *conrad = [[Person alloc] initWithFirst:@"Conrad" last:@"Kramer" birthdate:date];
BOOL equal = [cosmo isEqual:conrad];
NSLog(@"%@ and %@ are %@equal!", cosmo.first, conrad.first, (equal ? @"" : @"not "));
Cosmo and Conrad are equal!
[_first isEqual:object.first],
=>[_first isEqual:object.first] &&