session.py

import tensorflow as tf

state = tf.Variable(0 , name = 'counter')

one = tf.constant(1)

new_value = tf.add(state , one)
update = tf.assign(state , new_value)

init = tf.initialize_all_variables()

with tf.Session() as sess:
	sess.run(init)
	for _ in range(3):
		sess.run(update)
		print sess.run(state)