Is it possible to define the constructor with default arguments/parameters?
============================================================================
yes.

# Constructor with default arguments

class Employee:
    def __init__(self,name = 'User',pos = None,salary = None):
        self.ename = name
        self.epos = pos
        self.esal = salary

    def printData(self):
        print("The Employee Details are:")
        print("Name of the employee = ",self.ename)
        print("Position of the employee = ",self.epos)
        print("Salary of the employee = ",self.esal)

emp = Employee()    # without sending data to the class we can execute the constructor
emp1 = Employee(name = "Gazala")    # keyword argument representation
emp2 = Employee(name = "Hyma",salary=50000)
emp3 = Employee(name = "Amisha",salary=50000,pos="Associate Engineer")

emp.printData()
emp1.printData()
emp2.printData()
emp3.printData()
==============================================================

Constructor with Variable length Arguments:
===========================================

# Constructor with variable length arguments

class Calculator:
    def __init__(self,*args):
        self.data = args    # variable length arguments ==> tuple and that tuple ==> instance variable
        self.res = 0
        for i in self.data:
            self.res += i
        # return self.res
        print("The Sum = ",self.res)


    def addition(self):
        self.res = 0
        # td = self.data
        for x in self.data:
            self.res += x
        # return self.res
        print("The Sum = ",self.res)

cal = Calculator()  # with 0 parameters
cal1 = Calculator(121,123,125)

# print("The Sum = ",cal.addition())
# print("The Sum = ",cal.addition())
cal.addition()
cal1.addition()
=================================================
Polymorphism:
=============
Overriding:
===========

method: mult
method : add

# Overriding
# Method Overriding

class myClass:
    def __init__(self,a,b):
        self.a = a
        self.b = b

    def m1(self):
        return self.a + self.b

    def m1(self):
        return self.a * self.b

mc = myClass(100,200)
mc1 = myClass(23,29)

print("The Result = ",mc.m1())
print("The Result = ",mc1.m1())

===============================================
class Parent:
    def __init__(self,a,b):
        self.a = a
        self.b = b

    def met1(self):
        return self.a + self.b

class Child(Parent):
    def met1(self):
        print("The Product = ",self.a * self.b)

p = Parent(100,200)
c = Child(112,121)

print("The Result = ",p.met1())
c.met1()

============================================
X Bank:
	def personal_Loan(self):
		self.roi = 0
	
	def home_Loan(self):
		self.roi = 0

	def car_Loan(self):
		self.roi = 0

Icici Bank(X Bank):
	def personal_Loan(self):
		self.roi = 12.5
	
	def home_Loan(self):
		self.roi = 9.7

	def car_Loan(self):
		self.roi = 15%

Constructor Overriding:
=======================

# Constructor Overriding

class myClass:
    def __init__(self):
        print("Good Morning")

    def __init__(self,name):
        print("Hi",name,"Good Morning")

# mc = myClass()
mc = myClass("Keerthi")