Batch get assets history request.
.. attribute:: parent
Required. The relative name of the root
asset. It can only be an organization number
(such as "organizations/123"), a project ID
(such as "projects/my-project-id")", or a
project number (such as "projects/12345").
A list of the full names of the assets. See:
The request becomes a no-op if the asset name list is empty,
and the max size of the asset name list is 100 in one
Optional. The time window for the asset history. Both
start_time and end_time are optional and if set, it must be
after the current time minus 35 days. If end_time is not
set, it is default to current timestamp. If start_time is
not set, the snapshot of the assets at end_time will be
returned. The returned results contain all temporal assets
whose time window overlap with read_time_window.