Mockup: pattern sortable associating a callback function with drag and drop not working as expected

I'm looking at the Mockup sortable pattern, I'd like to add a callback function.
According to the docs I just need to assign a callback function to "drop" inside of the data-pat-sortable property.

So I did this:

<table data-pat-sortable="selector:tr;
                          class="listing table-stripped pat-sortable">
<tr><td>my thing</td></tr>
<tr><td>my other thing</td></tr>

I have a simple function that looks like this (just for testing).

            function reorderStatusAlerts(event){

I figured the callback would trigger some useful information on the console.

Dragging works, the selector and dragClass work as expected, but the callback doesn't, what I get as output on the console is the following error:

logged-in.js:24 Uncaught TypeError: b.options.drop is not a function
    at HTMLTableRowElement.<anonymous> (logged-in.js:24)
    at HTMLTableRowElement.dispatch (jquery.min.js:3)
    at HTMLTableRowElement.b.dispatch (default.js:2531)
    at HTMLTableRowElement.<anonymous> (default.js:2531)
    at Function.each (jquery.min.js:2)
    at n.fn.init.each (jquery.min.js:2)
    at Object.hijack (default.js:2531)
    at HTMLDocument.handler (default.js:2531)
    at HTMLDocument.dispatch (jquery.min.js:3)
    at HTMLDocument.b.dispatch (default.js:2531)
(anonymous)	@	logged-in.js:24
dispatch	@	jquery.min.js:3
b.dispatch	@	default.js:2531
(anonymous)	@	default.js:2531
each	@	jquery.min.js:2
each	@	jquery.min.js:2
hijack	@	default.js:2531
handler	@	default.js:2531
dispatch	@	jquery.min.js:3
b.dispatch	@	default.js:2531
r.handle	@	jquery.min.js:3

I'm really not sure what I'm missing at this point.

Options always seem to be converted to strings in mockup. I tried to fix this specific problem here: