input: Write a function to create a class in Python that implements two methods to add two numbers. The first method should take two arguments and return their sum, while the second method should take three arguments and return their sum. If any method is called with incorrect number of arguments, it should raise an exception.
  assert Calculator().add_two_numbers(1, 2) == 3
  assert Calculator().add(1, 2, 3) == 6
  assert Calculator().add_two_numbers(1, 2, 3) == Exception
  assert Calculator().add(1, 2) == Exception
output: class Calculator:
      def add_two_numbers(self, a, b):
          if len(locals()) != 3:
              raise Exception
          return a + b
      
      def add(self, a, b, c):
          if len(locals()) != 4:
              raise Exception
          return a + b + c