How to access yaml list / sequence (array to string conversion error)

I've written a list in my site.yaml:

--- yaml
times:
monday:

        - "08:00"
        - "13:00"
    -
        - "16:00"
        - "18:30"

I assumed, that the data would be accessible from the twig via

--- twig
site.times.monday.0.0

similar to json, but I get an error: An exception has been thrown during the rendering of a template ("Array to string conversion")

So how to access this data?

site.times.monday[0][0] should work