python - Am I using super() correctly? -

i made small chunk of code because i'm still trying figure out specifics of using super(). why chunk run typeerror?

 = secondclass() typeerror: __init__() takes 2 arguments (1 given) 

then, secondclass.meth() function supposed print string, i'm missing conceptually.

class firstclass (object):     def __init__ (self, value):         self.value = value         print self.value  class secondclass (firstclass):     def meth (self):         super (firstclass,self).__init__(value = "i strange string")  = secondclass() a.meth() 

this isn't super. don't define __init__ secondclass explicitly - but, because inherits firstclass, inherits firstclass's __init__. can't instantiate object without passing in value parameter.

edit ok. first point, others have mentioned, must use current class in super call, not superclass - in case super(secondclass, self). that's because super means "get parent of class x", mean "get parent of secondclass" - firstclass.

the second point doesn't make sense call __init__ method inside meth. __init__ already called when instantiate object. either subclass defines own version, can choose whether or not call own super method; or, in case, doesn't, in case superclass's version called automatically.

let me repeat that, because suspect missing piece in understanding: whole point of subclassing don't override, gets inherited anyway. super only cases when want override something, still use logic super class as well.

so here's silly example:

class firstclass(object):     def __init__ (self, value="i value firstclass"):         print value      def meth(self):         print "i meth firstclass"      def meth2(self):         print "i meth2 firstclass"  class secondclass(firstclass):     def __init__ (self):         print "i in secondclass"         super(secondclass, self).__init__(value="i value secondclass")      def meth(self):         print "i meth secondclass"   a=firstclass() # prints "i value firstclass" b=secondclass() # prints *both* "i in secondclass" *and* "i value secondclass  a.meth() # prints "i meth firstclass" b.meth() # prints "i meth secondclass"  a.meth2() # prints "i meth2 firstclass" b.meth2() # *also* prints "i meth2 firstclass", because didn't redefine it.