In Python you have to call initializing method of super class explicitly:
$ python -V
Python 3.6.3
$ cat << EOF > demo.py
class A:
def __init__(self, pa, pb):
print('init in class A')
self.pa = pa
self.pb = pb
class B(A):
def __init__(self, pa, pb):
print("init in class B")
super().__init__(pa, pb)
b = B(3, 2)
print(b.pa + b.pb)
EOF
$ python demo.py
init in class B
init in class A
5
Ref: https://stackoverflow.com/questions/2399307/how-to-invoke-the-super-constructor