The optional payload used in the request to start a new assignment via the WaniKani API.
https://docs.api.wanikani.com/20170710/#start-an-assignment
Specify properties of the Assignment; currently only started_at is supported.
started_at
Optional
When the assignment was started. Must be greater than or equal to the assignment's unlocked_at date.
unlocked_at
The optional payload used in the request to start a new assignment via the WaniKani API.
See
https://docs.api.wanikani.com/20170710/#start-an-assignment