How to disable RDS backups via CLI? Setting to one works, but not zero

Question

According to https://docs.aws.amazon.com/cli/latest/reference/rds/modify-db-instance.html, the way to disable backup retention is to provide 0 as the integer to the --backup-retention-period argument. However, this does not seem to work.

If I set the value to 1, it works, but not 0. There is actually no error when setting it to 0; it just simply doesn't make any changes.

Here's all I'm doing:

aws rds modify-db-instance --db-instance-identifier mydb --backup-retention-period 0

Is there another way to disable RDS backups?