Course1 - Week 2 - PA 2 - Logistic Regression with a Neural Network mindset about coursera-deep-learning-specialization HOT 2 OPEN

You are correct, the training and testing examples should be reshaped as:

train_set_x_flatten = train_set_x_orig.reshape(train_set_x_orig.shape[0], -1).T
test_set_x_flatten = test_set_x_orig.reshape(test_set_x_orig.shape[0], -1).T

from coursera-deep-learning-specialization.

A more shorter answer is

train_set_x_flatten = train_set_x_orig.reshape(-1, train_set_x_orig.shape[0])
test_set_x_flatten = test_set_x_orig.reshape(-1, test_set_x_orig.shape[0])

from coursera-deep-learning-specialization.