Converting string date to timestamp in python 3.4

Question

I am trying to convert string date to timestamp in Python as described in the post here. When I run the code examples in the post, I encounter an error. For e.g.:

Answer 1

Thanks to @J.F. Sebastian. I was caught in the name shadowing trap. I made the stupid mistake of naming one of my modules calendar.py. Once I removed this file, everything ran fine. I hope this post is not a waste and that someone may someday find it useful.