Nick Becker's Mail Room Assignment

Nick Becker's mailroom.py assignment for 12/8
This is very good policy.  The other option is to add a second `except` clause that covers the possible errors that might happen in successive lines of code.  The `ValueError` might be raised by the cast to `int`.  What could go wrong with appending?  If you aren't expecting there to be a problem there, then the line should be removed from the `except` clause into an `else` or just to after the entire block is completed.