input: Write a python function to initialize a class B that inherits from class A. The function should correctly initialize param1, param2 using the parent class's `__init__` method, and param3 should be an attribute of class B.
  ```python
  class A:
      def __init__(self, param1, param2):
          self.param1 = param1
          self.param2 = param2
  
  class B(A):
      def __init__(self, param1, param2, param3):
          super().__init__(param1, param2)
          self.param3 = param3
  ```
  assert B('value1', 'value2', 'value3').param1 == 'value1'
  assert B('value1', 'value2', 'value3').param2 == 'value2'
  assert B('value1', 'value2', 'value3').param3 == 'value3'
output: class A:
      def __init__(self, param1, param2):
          self.param1 = param1
          self.param2 = param2
  
  class B(A):
      def __init__(self, param1, param2, param3):
          super().__init__(param1, param2)
          self.param3 = param3