how to know how many clsss object do we have in python code example

Example: declare class python

# To create a simple class:
class Shape:
  	def __init__():
      	print("A new shape has been created!")
      	pass
    
    def get_area(self):
		pass

# To create a class that uses inheritance and polymorphism
# from another class:
class Rectangle(Shape):
  
	def __init__(self, height, width): # The constructor
    	super.__init__()
        self.height = height
    	self.width = width

	def get_area(self):
      	return self.height * self.width