How I can check if class attribute was defined or derived in given class in Python?

The code below shows the if the attribute 'foo' was defined or derived in the classes A and B.

Example

class A:
    foo = 1
class B(A):
    pass
print A.__dict__
#We see that the attribute foo is there in __dict__ of class A. So foo is defined in class A.
print hasattr(A, 'foo')
#We see that class A has the attribute but it is defined.
print B.__dict__
#We see that the attribute foo is not there in __dict__ of class B. So foo is not defined in class B
print hasattr(B, 'foo')
#We see that class B has the attribute but it is derived

Output

{'__module__': '__main__', 'foo': 1, '__doc__': None}
True
{'__module__': '__main__', '__doc__': None}
True