List of Arbitrary types not supported

Hi

I was adding some code to allow accepting list inputs & got this error when running the script

RuntimeError: Tracing a list of arbitrary type is currently not supported!

To which it leads me to https://github.com/pytorch/pytorch/blob/master/torch/csrc/jit/tracer.h

Apparently there’s also a similar error for dicts of arbitrary type.

Why is this error coming up in the first place, if I may ask?

Tracing can only record what happens to tensors, so a trace that involves lists of arbitrary type is high likely to produce incorrect results. Therefore we throw rather than silently change your output.