Fit_one_cycle() throws error int() argument must be a string, a bytes-like object or a number, not 'slice'

Hello all,

I am working my way through chapter 12 (lesson 8) where we construct a basic RNN model in LMModel1. When I create the learner and try to learn using learn.fit_one_cycle(4, 1e-3), I get the following error:

TypeError: int() argument must be a string, a bytes-like object or a number, not 'slice'

Is anybody else getting this error?

The notebook is here: Google Colaboratory

Additionally, when I try to do dls.show_batch() I get an error as well:

AttributeError: 'tuple' object has no attribute 'show'