To support the 'val_'+kwargs here:fastai/fastai#3133

Idea is to allow a little bit of hack-ability touse_kwargs_dict instead of writing specialdelegates function for my one off use case. Maybe not a good idea?

_wrap is reproducing the behavior indelegates, didn't want to change the default behavior ofuse_kwargs_dict, as I am not very familiar with its usage._wrap allows the stacking of multipleuse_kwargs_dict ordelegates when keep=True, otherwise they would error when**kwargs is removed by firstdelegates`use_kwargs_dict`. (tests should make this more clear).

Mostly looking for guidance here on if this makes sense, or if I should try something else. Here is example usage for easy reference:

@use_kwargs_dict(y=1,z=None)@use_kwargs_dict(x=2,wrap=True,keep=True)def foo(a, b=1, **kwargs): passtest_sig(foo, '(a, b=1, *, x=2, y=1, z=None)')@use_kwargs_dict(**{ 'val_'+k:v for k,v in get_kwargs_dict(foo).items()})@use_kwargs_dict(**get_kwargs_dict(foo),wrap=True,keep=True)def goo(g=4, **kwargs): passtest_sig(goo, '(g=4, *, b=1, x=2, y=1, z=None, val_b=1, val_x=2, val_y=1, val_z=None)')