Update calculator.py

kyu_3/calculator/calculator.py:42 in private method `__calculate`:
        D202: No blank lines allowed after function docstring (found 1)

        There's no blank line either before or after the docstring unless directly
        followed by an inner function or class.

kyu_3/calculator/calculator.py

@@ -41,7 +41,6 @@ def result(self) -> float:
     def __calculate(i: int, char: str, strings: list) -> None:
         """
         Calculate method.
-
         1. Perform math operation.
         2. Reorganize math expression.