what version of python do you use?

[elhammoumi]

I always have to modify your code to work for me, for example I add ( ) to print "".

[nbogdan]

I'd guess he is using python 2.7.x.
If you look in requirements.txt, you can see he uses tensorflow-0.11.0-cp27.

[HansGabriel]

I used python 3.7 but I just changed the https://storage.googleapis.com/tensorflow/linux/cpu/tensorflow-0.11.0-cp27-none-linux_x86_64.whl from the requirements.txt to tensorflow==1.4.0. Works properly for me.