chore: Fix ruff build failures (#14347)

machine_learning/linear_discriminant_analysis.py

@@ -47,7 +47,6 @@ from collections.abc import Callable
 from math import log
 from os import name, system
 from random import gauss, seed
-from typing import TypeVar
 
 
 # Make a training dataset drawn from a gaussian distribution
@@ -249,10 +248,7 @@ def accuracy(actual_y: list, predicted_y: list) -> float:
     return (correct / len(actual_y)) * 100
 
 
-num = TypeVar("num")
-
-
-def valid_input(
+def valid_input[num](
     input_type: Callable[[object], num],  # Usually float or int
     input_msg: str,
     err_msg: str,