Inheritance allows programmers to inherit the methods and attributes of one class to the other class.

This is really helpful when you want to use some useful methods of a class. Instead of coding it again ,we can simply derive from that class. This helps in avoiding repeated chunks of code and makes the code much more efficient.

In the code given below , we have 2 class ( Shape1 and Shape2 ) and we want to use the MyName method in Shape1 inside the Shape2 class using inheritance.

class Shape1():
  def __init__(self,shape_name):
    self.shape_name = shape_name
  def MyName(self):
    return 'I am a '+self.shape_name
    
class Shape2(Shape1):
  def __init__(self,shape_name):
     self.shape_name = shape_name
    

my_shape = Shape2('triangle')
print(my_shape.MyName())

I am a triangle

Inheritance also makes it possible to overwrite the definition of a method. To make changes , you'll have to basically redefine the whole method within your derived class. Say we want to make some changes ( in our derived class ) to the MyName method . So instead of returning the name of the shape , it returns the name of the class. This can be done in the following way:

 class Shape1():
  def __init__(self,shape_name):
    self.shape_name = shape_name
  def MyName(self):
    return 'I am a '+self.shape_name
    
class Shape2(Shape1):
  def __init__(self):
    pass # to avoid syntax error
  def MyName(self):
    return 'Shape2'
    

my_shape = Shape2()
print(my_shape.MyName()) 

Shape2

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Say there are 2 separate classes that happens to share a same method name , The ability to call the same method without worrying about specific class is called Polymorphism . This will become clear from the example below.

In the example given below , we have two classes ( Color1 and Color2 ) and both of these clases have a common method name called ColorName that returns the value of color attribute. First we will be performing polymorphism using for loops and then with functions.

Polymorphism using For loop

class Color_1():
  def __init__(self,color):
    self.color = color
  def ColorName(self):
    return self.color
  
class Color_2():
  def __init__(self,color):
    self.color = color
  def ColorName(self):
    return self.color

my_color1 = Color_1('green')
my_color2 = Color_2('red')

for x in [my_color1,my_color2]:
  print(x.ColorName())

green
red

Polymorphism using functions

class Color_1():
  def __init__(self,color):
    self.color = color
  def ColorName(self):
    return self.color
  
class Color_2():
  def __init__(self,color):
    self.color = color
  def ColorName(self):
    return self.color

my_color1 = Color_1('green')
my_color2 = Color_2('red')

def tellcolor(instance):
  print(instance.ColorName())
  
tellcolor(my_color1)
tellcolor(my_color2)

green
red