old_contents: def test_calculator_with_multiple_operations():
      calc = Calculator(
          operations={
              'add': AddOperation,
              'subtract': SubtractOperation
          }
      )
      res = calc.calculate(1, 5, 13, 2, 'add')
      assert res == 21
      
      res = calc.calculate(13, 3, 7, 'subtract')
      assert res == 3
  
new_contents: def test_calculator_with_multiple_operations():
      calc = Calculator(
          operations={
              'add': AddOperation,
              'subtract': SubtractOperation
          }
      )
      res = calc.calculate(1, 5, 13, 2, 'add')
      assert res == 21
  
      res = calc.calculate(13, 3, 7, 'subtract')
      assert res == 3
  
subject: Update test_calculator_with_multiple_operations.py