The files model.py and utils.py together provide necessary code to instantiate and
run PolySketchFormer.

Instructions:
1. Instantiate an object of class utils.TransformerConfig using the structure of
   the model to be used.
2. Create a `tree_of_sketches` object by calling model.naive_instantiate_all_tensor_sketches and appropriate random keys.
3. Create the model.Transformer object by using the config and tree_of_sketches variables and appropriate random keys.