__getattr__ is called if __getattribute__ raises an AttributeError. Raising AttributeError in __getattr__ is a bad idea...

except.py

>>> class AttrDict(dict):
...     """A class that is annoyingly difficult to get right in python."""
...     def __getattr__(self, attr):
...         """access items by key with dot notation"""
...         try:
...             return super(AttrDict, self).__getitem__(attr)
...         except KeyError as e:
...             raise AttributeError(e)  # translate the error where applicable yay
... 
>>> 
>>> class Something(AttrDict):
...     """Hey that attrdict thing looked neat lets build something on top"""
...     @property
...     def thing(self):
...         # code code code...
...         foo = self.something_else  # pretend this error is not obvious
...         # code code code...
...         return foo
...     
...     @property
...     def other_thing(self):
...         # code code code...
...         bar = self.thing
...         # code code code...
...         return bar
... 
>>> 
>>> my_thing = Something()
>>> print my_thing.other_thing
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 8, in __getattr__
AttributeError: 'other_thing'
>>> 
>>> # uh... that's weird... lets try putting in some print debugging...
... 
>>> class Something(AttrDict):
...     """Hey that attrdict thing looked neat lets build something on top"""
...     @property
...     def thing(self):
...         # code code code...
...         foo = self.something_else  # pretend this error is not obvious
...         # code code code...
...         return foo
...     
...     @property
...     def other_thing(self):
...         # code code code...
...         print 'DEBUG: getting that other_thing'
...         bar = self.thing
...         print 'DEBUG: other thing: ', bar
...         # code code code...
...         return bar
... 
>>> 
>>> my_thing = Something()
>>> print my_thing.other_thing
DEBUG: getting that other_thing
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 8, in __getattr__
AttributeError: 'other_thing'
>>> 
>>> # it was printing debugs from INSIDE other_thing, yet can't find other_thing?..
... 
>>>

more_simply.py

class AttrMesser(object):
    def __getattr__(self, attr):
        print("Nope! lol.")

    @property
    def no_just_kidding(self):
        print("Think you can raise attribute errors from here?")
        should_raise = self.nonexistent_attribute

    @property
    def no_really_now(self):
        print("What about with an explicit raise?")
        raise AttributeError
        # I suppose this could be a tricky way to defer to some other behavior
        # in __getattr__ from a property. And by tricky I mean terrible and I
        # would never use your library.


blah = AttrMesser()
blah.no_just_kidding
blah.no_really_now