What does "this.hello = this.hello;" do?

wat.js

function O1() {

}
function O2() {
    // what does this line do?
    this.hello = this.hello;
}

O1.prototype.hello = O2.prototype.hello = function() {
    console.log('hello');
};


var o1 = new O1(),
    o2 = new O2();

o1.hello(); // hello
o2.hello(); // hello


// so what does it do?


















console.log(o1.hasOwnProperty('hello')); // false
console.log(o2.hasOwnProperty('hello')); // true