Why is the program not running? Is there a logical or syntax problem?

[deanhystad]

You have some indentation errors. For example:

      def rule(master):
      return 72/master

rule() is not declared to be a static method. Either you need a @staticmethod decorator or add self as the first argument (def rule(self, master). I'm not sure which is correct, because rule() doesn't make any sense. What is "master" supposed to be?