OC判断用户输入的邮箱地址是否合法的代码

OC判断用户输入的邮箱地址是否合法的代码?

- (BOOL) isEmail: (NSString *) emailAddress {    NSString *regex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";     NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];     return [emailTest evaluateWithObject:emailAddress];}