I am trying out stripe payment integration in iOS app using [this](https://stripe.com/docs/mobile/ios#applepay) link. 

I am getting the following error:

```
    +[Stripe paymentRequestWithMerchantIdentifier:amount:currency:description:]: unrecognized selector sent to class 0x10ecc73d0
2014-10-13 12:04:50.029 stripeDemoApplePay[2507:71067] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[Stripe paymentRequestWithMerchantIdentifier:amount:currency:description:]: unrecognized selector sent to class 0x10ecc73d0'

```

Following is the code where am getting this error:

```
    - (IBAction)beginPayment:(id)sender {
    NSString *merchantId = @"my merchant id";
    NSInteger price = 10;
//    NSUInteger *numberOfShirts = ;
    NSDecimalNumber *amt = [NSDecimalNumber decimalNumberWithMantissa:price exponent:0 isNegative:NO];;
    PKPaymentRequest *paymentRequest = [Stripe paymentRequestWithMerchantIdentifier:merchantId
                                                                             amount:amt
                                                                           currency:@"USD"
                                                                        description:@"Premium Llama Food"]; //ERROR LINE
    [paymentRequest setRequiredShippingAddressFields:PKAddressFieldPostalAddress];
    [paymentRequest setRequiredBillingAddressFields:PKAddressFieldPostalAddress];

```

Where am I getting wrong? how do I solve this?