Whether or not the user currently has a paid subscription.
The maximum level of content accessible to the user for lessons, reviews, and content review. For unsubscribed/free
users, the maximum level is 3. For subscribed users, this is 60.
Any application that uses data from the WaniKani API must respect these access limits.
The date when the user's subscription period ends. If the user has subscription type lifetime or free then the
value is null.
The type of subscription the user has. Options are following: free, recurring, and lifetime. A type of
unknown means the user subscription state isn't exactly known. This is a weird state on WaniKani, should be
treated as free, and reported to the WaniKani developers.
Details about the user's subscription state.
See
https://docs.api.wanikani.com/20170710/#user