non-obvious behavior of the "bunch"

[Alexei M.]

Python 3.2.3 (default, Apr 12 2012, 19:08:59)
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
import tempita
>>> bunch = tempita.bunch(default=None)
>>> bunch.b
>>> print(bunch.b)
None
>>> bunch2 = bunch.copy()
>>> print(bunch2.b)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'dict' object has no attribute 'b'

Using hack for python3:
....

>>> def copy(self):
... return self.__class__(**dict(self.items()))
...
>>> tempita.bunch.copy = copy
>>> bunch = tempita.bunch(default=None)
>>> print(bunch.b)
None
>>> bunch2 = bunch.copy()
>>> print(bunch2.b)
None