What are class members? How do you define it?

Write a class with two private class variables and print the sum using a method.

Find the error in the following program to get the given output?
class Fruits:
def __init__(self, f1, f2):
self.f1 = f1
self.f2 = f2
def display(self):
print("Fruit 1 = %s, Fruit 2 = %s" %(self.f1, self.f2))
F = Fruits ('Apple', 'Mango')
del F.display
F.display()

What is the output of the following program?
class Greeting:
def __init__(self, name):
self.__name = name
def display(self):
print("Good Morning ", self.__name)
obj=Greeting ('Bindu Madhavan')
obj.display()

How to define constructor and destructor in Python?