Write a python code that explains the Polymorphism?

class Bird: 
  def intro(self):
    print("We are birds!") 
  
  def flight(self): 
    print("Wow we can fly but some cannot.")
  
class crow(Bird): 
  def flight(self): 
    print("Crows can fly.") 
  
class ostrich(Bird): 
  def flight(self): 
    print("Ostriches cannot fly.") 
  
obj_bird = Bird() 
obj_cro = crow() 
obj_ost = ostrich() 
obj_bird.intro() 
obj_bird.flight() 
obj_cro.intro() 
obj_cro.flight() 
obj_ost.intro() 
obj_ost.flight() 

Output:

We are birds!
Wow we can fly but some cannot.
We are birds!
Crows can fly.
We are birds!
Ostriches cannot fly.