'Update a HIT with a status of Reviewable to have a status of Reviewing,
or reverts a Reviewing HIT back to the Reviewable status.
Only HITs with a status of Reviewable can be updated with a status of
Reviewing.  Similarly, only Reviewing HITs can be reverted back to a
status of Reviewable.'

def set_reviewing(self, hit_id, revert=None):

    params = {'HITId': hit_id}
    if revert:
        params['Revert'] = revert
    return self._process_request('SetHITAsReviewing', params)
