Python supports multiple inheritances of classes. Conventionally (not a language rule), private variables and methods are declared by being preceded with two underscores (__). We can assign arbitrary attributes (properties) to the instances of a class, as shown in the following example:

class FirstClass:
    common_value = 10
    def __init__ (self):
        self.my_value = 100
    def my_func (self, arg1, arg2):
        return self.my_value*arg1*arg2

# Build a first instance
>>> first_instance = FirstClass()
>>> first_instance.my_func(1, 2)
200

# Build a second instance of FirstClass
>>> second_instance = FirstClass()

#check the common values for both the instances
>>> first_instance.common_value
10

>>> second_instance.common_value
10

#Change common_value for the first_instance
>>> first_instance.common_value = 1500
>>> first_instance.common_value
1500

#As you can note the common_value for second_instance is not changed
>>> second_instance.common_value
10


# SecondClass inherits from FirstClass. 
# multiple inheritance is declared as follows:
# class SecondClass (FirstClass1, FirstClass2, FirstClassN)

class SecondClass (FirstClass):
    # The "self" argument is passed automatically
    # and refers to the class's instance
    def __init__ (self, arg1):
        self.my_value = 764
        print (arg1)

>>> first_instance = SecondClass ("hello PACKT!!!!")
hello PACKT!!!!

>>> first_instance.my_func (1, 2)
1528