[Python] Why don't my subclass instances contain the attributes from the base class (causing...

I have this base class and subclass:

class Event:
def __init__(self, sr1=None, foobar=None):
self.sr1 = sr1
self.foobar = foobar


# Event class wrappers to provide syntatic sugar
class TypeTwoEvent(Event):
def __init__(self, level=None):
self.sr1 = level


Later on, when I try to check the foobar attribute of a TypeTwoEvent instance, I get an exception. For example, testing this at the REPL:

>>> event = TypeTwoEvent()
>>> event.foobar
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'TypeTwoEvent' object has no attribute 'foobar'


I thought that the base class attributes would be inherited by the subclass and that creating an instance of a subclass would instantiate the base class (and thus invoke its constructor). Therefore, I expected the foobar attribute value to be defaulted to None.

Why do TypeTwoEvent instances not have a foobar attribute, even though Event instances do?

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