Too Long; Didn't Read
Short Guide to Best Practices When Naming Variables in Python is published at http://dev.to/aswin2001barath/variables-in-Python-12d3. Python is case sensitive, which means variables like hello and Hello are completely different in python. Do not use special characters like!@,#,$%,%% and/# in a variable name, because you will get the same error message: "./program.py", line (x), in < module>