Registers a forward pre-hook on the module.
The hook will be called every time before
forward()is invoked. It should have the following signature:
hook(module, input) -> None or modified input
The input contains only the positional arguments given to the module. Keyword arguments won’t be passed to the hooks and only to the
forward. The hook can modify the input. User can either return a tuple or a single modified value in the hook. We will wrap the value into a tuple if a single value is returned(unless that value is already a tuple).