<object_hash>
values obtained from the label_row["labels"]["<frame_number>"]["objects"]
entry in the label row. An object (identified by its <object_hash>) is interpolated between the key frames where it is present.
The interpolation algorithm can be run on multiple objects with different ontological objects at the same time (for example, you can run interpolation on bounding box, polygon, and keypoint, using the same function call) on any number of key frames.