__dict__ is neato torpedo!

[Andrew Berg]

I'm pretty happy that I can copy variables and their value from one
object's namespace to another object's namespace with the same variable
names automatically:

class simpleObject():
    pass

a = simpleObject()
b = simpleObject()

a.val1 = 1
a.val2 = 2
b.__dict__.update(a.__dict__)
a.val1 = 'a'

>>> a.val1
'a'
>>> a.val2
2
>>> b.val1
1
>>> b.val2
2

The reason I'm posting this is to ask what to watch out for when doing
this. I've seen vague warnings that I don't really understand, and I'm
hoping someone can enlighten me.