"is_sandox" request parameter for subscription revoking

Hi!

Recently I've found out that it is possible to grant/prolong subscription with is_sandbox parameter in the request body. It works brilliantly for me (except that API responds "Not a valid string" on the boolean "is_sandbox" parameter, but if I pass it as a string "true" all works fine :))

I see an expected event from Sendbox environment on every granting with is_sandbox flag. But when I want to revoke a granted subscription I can't find how to specify the environment of the transaction.
When revoking a subscription I always see Production environment in event feed.

Could you please make it possible to specify the environment for revoking the subscription?

Respectfully,
Vitaliy