could not understand the whole code system
function lookUpProfile(firstName, prop){
// Only change code below this line
var answer = "No such contact";
contacts.some(function (arg) {
if (arg.firstName === firstName && arg.hasOwnProperty(prop) === true) {
answer = arg[prop];
} else if (arg.hasOwnProperty(prop) === false) {
answer = "No such property";
}
});
return answer;