input: Write a python function to create an Employee class and instantiate it with name and salary attributes.
  assert e1.name == "John"
  assert e1.salary == 15000
  assert e2.name == "Mary"
  assert e2.salary == 12000
output: def create_employee_class():
      class Employee:
          def __init__(self, name, salary):
              self.name = name
              self.salary = salary
  
      e1 = Employee("John", 15000)
      e2 = Employee("Mary", 12000)
      return e1, e2
  
  e1, e2 = create_employee_class()