[web2py] class example on book

[黄祥]

hi,

is there any class example on book or appliances, so that i can learn
from it?
i've already tried the simple things what written on book, but got an
error. do you have any hints or solutions?
thank you so much before

e.g.
=== controller ===

class MyClass(object):
    z = 2
    def __init__(self, a, b):
        self.x = a, self.y = b
    def add(self):
        return self.x + self.y + self.z

def index():
    myinstance = MyClass(3, 4)
    add = myinstance.add()
    return dict(add = add)

=== view ===
{{add}}