Implement argparse in throw_err.py

If you haven’t done so already, fork and clone the repository at https://github.com/cs294-python/errors. This code works fine, but could be cleaner. Use the built in argparse library to simplify handling command line arguments.

There is more than one way to accomplish this. You’ll get a point if your code

• Uses argparse
• Still throws errors based on arguments

NOTE: By those criteria, it is okay if your code requires slightly different arguments than the original version. For example, it’s acceptable to require typing

python throw_err.py --assertion

as opposed to

python throw_err.py assertion

BTW here is how (and when) I learned about argparse :)