public KnetikApiResponse CartAddDiscount(
string sku,
Action<KnetikApiResponse> cb = null
)
{
JSONObject j = new JSONObject (JSONObject.Type.OBJECT);
j.AddField ("sku", sku);
String body = j.Print ();
KnetikRequest req = CreateRequest(CartAddDiscountEndpoint, body);
KnetikApiResponse response = new KnetikApiResponse(this, req, cb);
return response;
}