How to get html_select values in Dash.jl

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1

I gave Dash.jl a try and it looks really nice! I have, however, a question:
Suppose I have the following code:

using Dash, DashHtmlComponents, DashCoreComponents

app = dash()
app.layout = html_div() do
            html_tr((html_td("msg = "), html_td(id = "msg"))),
            html_div(id = "navigation") do
                html_select(id="DD", multiple=true, size=5,
                children=(
                html_option("aaa"),
                html_option("bbb"),
                html_option("ccc")
                )
                )
            end
        end

callback!(
    app,
    Output("msg", "children"),
    Input("DD", "id"),
) do x
    @info x
    return x
end

run_server(app, "127.0.0.1", debug=true)

How can I get the selection from the html_select?
I don’t want to use dcc_dropdown because I like seeing more values in list and it’s much easier to select multiple items with html_select.