input: Write a python function to create an Employee object and test its methods.
  assert e.get_full_name() == "John Doe"
  assert e.get_annual_salary() == 60000
  
  e = Employee("Jane", "Smith", 7000)
  assert e.get_full_name() == "Jane Smith"
  assert e.get_annual_salary() == 84000
  
  e = Employee("Emily", "Davis", 5000)
  assert e.get_full_name() == "Emily Davis"
  assert e.get_annual_salary() == 60000
output: class Employee:
      def __init__(self, first_name, last_name, monthly_salary):
          self.first_name = first_name
          self.last_name = last_name
          self.monthly_salary = monthly_salary
  
      def get_full_name(self):
          return f"{self.first_name} {self.last_name}"
  
      def get_annual_salary(self):
          return self.monthly_salary * 12
  
  # Creating an Employee object and testing its methods
  e = Employee("John", "Doe", 5000)
  assert e.get_full_name() == "John Doe"
  assert e.get_annual_salary() == 60000
  
  e = Employee("Jane", "Smith", 7000)
  assert e.get_full_name() == "Jane Smith"
  assert e.get_annual_salary() == 84000
  
  e = Employee("Emily", "Davis", 5000)
  assert e.get_full_name() == "Emily Davis"
  assert e.get_annual_salary() == 60000