# coding:utf-8
      """
      So far we have created a child class that inherits 
      the properties and methods from its parent.
      We want to add the __init__() function to 
      the child class (instead of the pass keyword).
      Note: The __init__() function is called automatically 
      every time the class is being used to create a new object.
      """
      class Person:
        def __init__(self, fname, lname):
          self.firstname = fname
          self.lastname = lname
      
        def printname(self):
          print(self.firstname, self.lastname)
      
      """
      When you add the __init__() function, 
      the child class will no longer inherit the parent's __init__() function.
      The child's __init__() function 
      overrides(無効する) the inheritance of the parent's __init__() function.
      
      To keep the inheritance of the parent's __init__() function, 
      add a call to the parent's __init__() function:
      class Student(Person):
        def __init__(self, fname, lname):
          Person.__init__(self, fname, lname)
      """   
      
      #override case1 
      class Student(Person):
         def __init__(self, fname):
           self.firstname = fname
         def printname(self):
           print(self.firstname)
           
      x = Student("Gorge")
      x.printname()
      
      #override case2 
      class Student(Person):
         def __init__(self, fname, mname,lname):
           Person.__init__(self, fname, lname)
           self.middlename = mname
           
         def printname(self):
           print(self.firstname,self.middlename,self.lastname)
           
      x = Student("Gorge","Ben","Bridgeton")
      x.printname()