import tensorflow as tf

import os

# Just disables the warning, doesn't enable AVX/FMA
os.environ['TF_CPP_MIN_LOG_LEVEL'] = '2'

a = tf.constant(1.2)

b = tf.constant(2.8)

c = a + b

c

<tf.Tensor 'add:0' shape=() dtype=float32>

# You can see the value is not updated as it is just a model

with tf.Session() as sess:
    print(sess.run(c))
    print(c)

4.0
Tensor("add:0", shape=(), dtype=float32)

c

<tf.Tensor 'add:0' shape=() dtype=float32>