import tensorflow as tf

sess = tf.Session

a = tf.placeholder(tf.float32)
b = tf.placeholder(tf.float32)
adder_node = a + b

print(sess.run(adder_node, feed_dict={a: 3, b: 4.5}))
print(sess.run(adder_node, feed_dict={a: [1, 3], b:[2, 4]}))

