Problem: Search hyper parameters for a deep feed forward neural network in MS homework, you are going to
Part 1: Practice using Keras to Implement a neural network and search its hyper parameters for handwritten digits classification.
Part 2: The framework. e.g. The main function and functions' names. input, and output, has been defined. You are required to complete the create_NN, nn_params_search, retrain_best_nn. performanceacc functions.
Part 3: Add your code in the following blocks, and do not change other places.