def max_pool_2x2(x):
    return tf.nn.max_pool(x, ksize=[1, 2, 2, 1],
                          strides=[1, 2, 2, 1], padding='SAME')

# get mnist data
null graph has empty node boundaries
dataset/ETHPy150Open longubu/datumio/examples/tensorflow/mnist_cnn.py/max_pool_2x2--crossover with--dataset/ETHPy150Open gkno/gkno_launcher/src/networkx/algorithms/tests/test_boundary.py/TestBoundary.test_null_node_boundary