input: Write a function to define a class `Calculator` in Python that implements two methods to add two numbers and three numbers respectively. The first method should be named `add_two_numbers` and take two arguments, while the second method should be named `add` and take three arguments. If the methods are implemented correctly, the class should return the sum of the provided numbers.
  
  
  class Calculator:
      def __init__(self):
          pass
  
      def add_two_numbers(self, a, b):
          return a + b
  
      def add(self, a, b, c):
          return a + b + c
  
  assert Calculator().add_two_numbers(1, 2) == 3
  assert Calculator().add(1, 2, 3) == 6
  assert Calculator().add_two_numbers(-5, 5) == 0
  assert Calculator().add(10, -2, 3) == 11
  
output: class Calculator:
      def __init__(self):
          pass
  
      def add_two_numbers(self, a, b):
          return a + b
  
      def add(self, a, b, c):
          return a + b + c