code: def set_all_revisions_to_in_process(self, ids):
          
  
          predicate = {
              "_id" : {
                  "$in" : [ ObjectId(id) for id in ids ]
              }
          }
  
          set = {"$set": { "inProcess": True }}
  
          yield self.revisions.collection.update(predicate, set, multi=True)
docs: Set all revisions found to in process, so that other threads will not pick them up.
  
          :param list ids: