code: def layer_sizes(X, Y):
      
      n_x = X.shape[0]  # size of input layer
      n_h = 4
      n_y = Y.shape[0]  # size of output layer
      return (n_x, n_h, n_y)
docs: Arguments:
      X -- input dataset of shape (input size, number of examples)
      Y -- labels of shape (output size, number of examples)
  
      Returns:
      n_x -- the size of the input layer
      n_h -- the size of the hidden layer
      n_y -- the size of the output layer