Exercise: Enron

Object Oriented Programming provides a way to reuse software. When you reuse classes you often need to adapt it in a particular way by adding or modifying behavior or data. One way of doing this is to create a new class that extends the existing one using the pattern of inheritance.

Imagine that you have been using the Email class found in the attached file enron.py. You would like the class to provide access to the Subject of the email (which can be found by searching for the first occurence of "Subject" at the beginning of a line in the text of the email). But you don’t want to change the behavior of the Email class itself because other people are using it already. Write a new class called ExtendedEmail that provides this additional method get_subject().

You can download the enron-sample.zip as test data for this exercise. Any of the files contained in that zip archive is an email message that should have a subject line.