Multiple inheritance in Python: how does super().__init__ affect?

Question

Can you please explain the following contradiction?

For this code:

class CL1(object):
    def __init__(self):
        super(CL1, self).__init__()
        print "class 1"


class CL2(object):
    def __init__(self):
        #super(CL2, self).__init__()
        print "class 2"


class CL3(CL2, CL1):
    def __init__(self):
        super(CL3, self).__init__()
        print "class 3"


instance = CL3()

the output is:

class 2

class 3

However, if I uncomment the line:

#super(CL2, self).__init__()

I get the output:

class 1

class 2

class 3

I don't understand why applying to the superclass of CL2 invokes the constructor of CL1. CL1 is not the constructor of CL2.

The link: How does multiple inheritance work with the super() and different __init__() arguments? doesn't explain why the line:

#super(CL2, self).__init__()

invokes the constructor of a class that is not the superclass of the class calling it.