Pyupgrade to Python 3.9 (#4718)

* Pyupgrade to Python 3.9

* updating DIRECTORY.md

Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>

electronics/electric_power.py

@@ -1,9 +1,10 @@
 # https://en.m.wikipedia.org/wiki/Electric_power
+from __future__ import annotations
+
 from collections import namedtuple
-from typing import Tuple
 
 
-def electric_power(voltage: float, current: float, power: float) -> Tuple:
+def electric_power(voltage: float, current: float, power: float) -> tuple:
     """
     This function can calculate any one of the three (voltage, current, power),
     fundamental value of electrical system.

electronics/ohms_law.py

@@ -1,8 +1,8 @@
 # https://en.wikipedia.org/wiki/Ohm%27s_law
-from typing import Dict
+from __future__ import annotations
 
 
-def ohms_law(voltage: float, current: float, resistance: float) -> Dict[str, float]:
+def ohms_law(voltage: float, current: float, resistance: float) -> dict[str, float]:
     """
     Apply Ohm's Law, on any two given electrical values, which can be voltage, current,
     and resistance, and then in a Python dict return name/value pair of the zero value.