def update(self, doc, process=None):
        if process is None:
            pk = 'id'
            id = doc.id
            doc.synced = False
            set = doc
        elif process == UPDATE_PROCESS:
            if self.db.docs.find({'sid': doc.sid}).count() == 0:
                return self.insert(doc, synced=True)
            pk = 'sid'
            id = doc.sid
            doc.synced = not doc.merged() # must be commited if was merged
            doc.merged(False)
            set = {'tid': doc.tid, 'data': doc.data, 'user': doc.user,
                   'public': doc.public, 'synced': doc.synced}
        elif process == COMMIT_PROCESS:
            pk = 'id'
            id = doc.id
            doc.synced = True
            set = {'sid': doc.sid, 'tid': doc.tid, 'synced': doc.synced}
        else:
            raise DatabaseException('Incorrect update process')

        try:
            rs = self.db.docs.update({pk: id}, {'$set': set}, safe=True)
            assert rs['n'] == 1
        except Exception as e:
            raise DatabaseException(e)
        return doc
def __init__(self, root, split="train", transforms=None):
        super().__init__(root=root, transforms=transforms)

        verify_str_arg(split, "split", valid_values=("train", "val"))

        root = Path(root) / "FlyingChairs"
        images = sorted(glob(str(root / "data" / "*.ppm")))
        flows = sorted(glob(str(root / "data" / "*.flo")))

        split_file_name = "FlyingChairs_train_val.txt"

        if not os.path.exists(root / split_file_name):
            raise FileNotFoundError(
                "The FlyingChairs_train_val.txt file was not found - please download it from the dataset page (see docstring)."
            )

        split_list = np.loadtxt(str(root / split_file_name), dtype=np.int32)
        for i in range(len(flows)):
            split_id = split_list[i]
            if (split == "train" and split_id == 1) or (split == "val" and split_id == 2):
                self._flow_list += [flows[i]]
                self._image_list += [[images[2 * i], images[2 * i + 1]]]