api call for mortage info

int CALCULATE_MORTGAGE_PAYMENT(int loan_amount, float interest_rate)
{
header_data = Map();
header_data.put("X-Api-Key","*************************");
calc_mortgage = invokeurl
[
	url :"https://api.api-ninjas.com/v1/mortgagecalculator?loan_amount=" + loan_amount + "&interest_rate=" + interest_rate + "&duration_years=30"
	type :GET
	headers:header_data
];
//info calc_mortgage;
ifNull(calc_mortgage.getJSON("monthly_payment").getJSON("mortgage"),0);
return monthly_payment;
}