Notebook function clarification needed

[nkorinek]

There are two functions in the notebook module that need clarification as to when they should be used and how.

1. The error_test() function seems to only compare two numbers and see if they are equivalent or not. It prints out a custom error message based on the comparison. When is this used? Is there a way to make the code more robust to make it easier to incorporate into a work flow and make it's purpose more obvious?

2. The remove_comments() function removes all commented lines in a string. When is this used in the workflow for notebook grading?
   Side note: The remove_comments() function used to leave empty spaces where it took out comments. I changed it so it deleted the line all together. The code used to look like this for records sake/if we decide to change it back:

return "".join([line.split("#")[0] for line in split_lines]) 

Clarification on these two functions would be greatly appreciated so we can document them better!