raise_amt = 1.20

def __init__(self,name,age,pay):
    self.name  = name
    self.age   = age
    self.pay   = pay
    self.email = name + '@hotmail.com'

def apply_raise(self):
    self.pay = int(self.pay * self.raise_amt)

emp1 = Emp('abcd',23,30000)
emp2 = Emp('PQRS',26,20000)

print(self.pay)
emp1.apply_raise()
print(self.pay)

class Emp:
    raise_amt = 1.20

    def __init__(self,name,age,pay):
        self.name  = name
        self.age   = age
        self.pay   = pay
        self.email = name + '@hotmail.com'

    def apply_raise(self):
        self.pay = int(self.pay * self.raise_amt)

emp1 = Emp('abcd',23,30000)
emp2 = Emp('PQRS',26,20000)

print(emp1.pay)
emp1.apply_raise()
print(emp1.pay)

>>> class Test:
...     def foo(bar):
...             print(repr(bar))
...
>>> a = Test()
>>> a.foo()
<__main__.Test object at 0x10a4bf9e8>
>>> b = Test()
>>> b.foo()
<__main__.Test object at 0x10a4bfa58>