tf.Session

import tensorflow as tf
import numpy as np

matrix1 = tf.constant([[3,3]])
matrix2 = tf.constant([[2],
                       [2]])
product = tf.matmul(matrix1, matrix2)
# method1
sess = tf.Session()
print(sess.run(product))
sess.close()

#method2
with tf.Session() as sess:
    print(sess.run(product))