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Old Style classes and inheritance
Objects - Intermediate example from a Well House Consultants training course
More on Objects - Intermediate [link]

This example is described in the following article(s):
   • TypeError: super() argument 1 must be type, not classobj (Python) - [link]

Source code: cl_o.py Module: Y112
"""Short demonstration of a group of classes in Python. There's
a base class called "pubtrans" which defines all types of public
transport that the application supports, and two derived classes
called "bus" and "train" which start off with "pubtrans" as their
basis and are then extended to add extra code and replace the
code which is in the base class as it applied to most (but not
all) piecees of public transport. The demonstration file also
includes a short piece of text code to show how it works, and to
allow you to run it stand alone to validate that it's been installed
correctly and that all dependencies are available.

This example uses OLD STYLE CLASSES. You should avoid using old
style classes in new code (see cl_n.py for the alternative new
style classes), and old style classes are no longer supported from
Python 3.x

A full application (rather than just a demo such as this) should
include documentation strings, and the test harness would be better
written using the doctest or unittest modules"""


class pubtrans:
        def __init__(self,about):
                self.info = about
        def getabout(self):
                return self.info
        def getvehicles(self):
                return 1
class train(pubtrans):
        def __init__(self,about,vehicle_capacity,coaches):
                pubtrans.__init__(self,about)
                self.vc = vehicle_capacity
                self.nc = coaches
        def getcapacity(self):
                return self.vc * self.nc
        def getvehicles(self):
                return self.nc
class bus(pubtrans):
        def __init__(self,about,vehicle_capacity):
                pubtrans.__init__(self,about)
                self.vc = vehicle_capacity
        def getcapacity(self):
                return self.vc
if __name__ == "__main__":
        testgroup = [train("First Great Western cl 150",80,2)]
        testgroup.append(bus("First Avon and Somerset",81))
        testgroup.append(bus("Faresaver",29))
        testgroup.append(train("South West Trains cl 159",75,3))
        format = "%-30s %4d %d"
        tpc = 0
        tvc = 0
        for option in testgroup:
                text = option.getabout()
                pass_count = option.getcapacity()
                veh_count = option.getvehicles()
                tpc += pass_count
                tvc += veh_count
                print format % (text, pass_count, veh_count)
        print format % (" --- TOTAL ---",tpc,tvc)


Learn about this subject
This module and example are covered on the following public courses:
 * Learning to program in Python
 * Python Programming
 * Intermediate Python
Also available on on site courses for larger groups

Books covering this topic
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Other Examples
This example comes from our "Objects - Intermediate" training module. You'll find a description of the topic and some other closely related examples on the "Objects - Intermediate" module index page.

Full description of the source code
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