Dataloader issue in Kaggle Global Wheat detection dataset

I am trying to build models for this archived competition using FastAI:

Here is my notebook:
I am unable to correctly display a batch from a dataloader and not sure where the show_batch call is failing exactly

A few questions:

  1. How can I display a few batches in text using dataloaders will this work - next(iter(fastai_dataloader))
  2. Can someone take a look at the notebook and comment what I am doing wrong?