super in python 2.7 [duplicate]

Question

I'm trying to understand how to use super in python

class people:   
 name = ''  
 age = 0  
  __weight = 0  

 def __init__(self,n,a,w):  
    self.name = n  
    self.age = a  
    self.__weight = w  
def speak(self):  
    print("%s is speaking: I am %d years old" %(self.name,self.age))  


class student(people):  
 grade = ''  
 def __init__(self,n,a,w,g):  
    #people.__init__(self,n,a,w)  
    super(student,self).__init__(self,n,a,w)
    self.grade = g  

 def speak(self):  
    print("%s is speaking: I am %d years old,and I am in grade %d"%(self.name,self.age,self.grade))  


s = student('ken',20,60,3)  
s.speak()

The above code gets following error:

---------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-147-9da355910141> in <module>()
     10 
     11 
---> 12 s = student('ken',20,60,3)
     13 s.speak()

<ipython-input-147-9da355910141> in __init__(self, n, a, w, g)
      3     def __init__(self,n,a,w,g):
      4         #people.__init__(self,n,a,w)
----> 5         super(student).__init__(self,n,a,w)
      6         self.grade = g
      7 

TypeError: must be type, not classobj

I'm confused about why I cannot use super(student,self).__init__(self,n,a,w) in this case, and why I have to use people.__init__(self,n,a,w)

Any help?

Answer 1

Your base class people should be derived from the object class, to make it a new-style class, which will allow super() to work.

You should then use super as:

super(student, self).__init__(n,a,w)

Old-style classes behave quite differently, and I don't understand them