Set a quota (in bytes) on this user library.  The quota is 'best effort',
        and should be set conservatively.

        A quota of 0 is 'unlimited'

def set_quota(self, quota_bytes):
        """
        Set a quota (in bytes) on this user library.  The quota is 'best effort',
        and should be set conservatively.

        A quota of 0 is 'unlimited'
        """
        self.set_library_metadata(ArcticLibraryBinding.QUOTA, quota_bytes)
        self.quota = quota_bytes
        self.quota_countdown = 0