How to use a callback function on angucomplete-alt selected-object attribute?

I digged the example from: Angucomplete Alt and I find out that you must provide the selected-object like this, even if It's a callback function:

<angucomplete-alt id="skill1"
                selected-object="addSkill"
                remote-url="@Url.Action("GetSkills", "ManageMission")/?query="
                title-field="Name"
                minlength="1"
                match-class="angucomplete-match"
                input-class="form-control"
                template-url="@Url.Content("~/Templates/angucomplete-alt.html")"></angucomplete-alt>

And the callback method should receive the selected item as parameter:

$scope.addSkill = function (selected) {
    console.log(selected); 
};