input: Write a function to create a Python class named Calculator that implements two methods: add_two_numbers to add two numbers and add to add three numbers. The function should return an instance of the class and should allow calling both methods with appropriate parameters and printing the results.
  
  assert isinstance(Calculator(), Calculator)==True
  assert Calculator().add_two_numbers(1, 2)==3
  assert Calculator().add(1, 2, 3)==6
  calculator = construct_calculator()
  result = calculator.add_two_numbers(1, 2)
  print(result)
output: def construct_calculator():
      class Calculator:
          def add_two_numbers(self, a, b):
              return a + b
          
          def add(self, a, b, c):
              return a + b + c
      
      return Calculator()