Suppose your work for the University of Michigan. The university wants to implement an email spam filter. So use the mbox.txt file that we used in class, build a filter system that filters emails into several categories of security levels: level 1 is the email from Of M (@ umich.edu), level 2 is the email from other North American universities (@ xyz.edu), level 3 is the email from other educational institutions around the world (.uct, .zA, etc.), and level 4 is the email from other email services (g m ail, etc). Please print out these 4 levels and also list all the senders (only those in the "From" lines) in each category. Example output: Level 1: zine@ umich.edu Level 2: Louis@ media.berkeley.edu ray@ media.berkeley.edu mummy@ indiana.edu Level 3: entrain@ caret.cam.ac.uk david.horwitz@ uct.ac.za Level 4: gopal.ramasammycook@ g mail.com