class A(): pass
a = A()
b = A()
a.b = b
b.c = 1
a.b # this is b
getattr(a, "b") # so is this
a.b.c # this is 1
getattr(a, "b.c") # this raises an AttributeError
It seemed very natural to me to assume the latter. I'm sure there is a good reason for this. What is it?