Returns one occurrence by the opaque occurrence_id obtained from the calendar
endpoint.

The response contains two type_specific objects with different meanings: the one inside template holds the
definitions (temperature ranges with min_temperature/max_temperature, checklist labels), while the top-level
one holds the values entered on completion (temperatures as {key, title, value}, checklist as the labels of
the checked items).

history lists previous versions of the completion, newest first, up to 50 entries; the current version is in
completion.

The possible values of template.type and completion.result are listed on the
Reference Values page.