Hyperparameter tuning in the model for better performance by introduction of callback function.

[Rishi2003Das]

Describe the bug
Finetuning the model of Lymphoma Cancer Classification and introducing a callback fuction to get the best epoch.
To Reproduce
Steps to reproduce the behavior:

1. Go to Breadcrumbstfjs-models/Classification Sample Models/lymphoma-cancer-classification
   /model.ipynb

Expected behavior
Better learning rate with a callback function to get the best epoch and thus best result.

Thank you