Add Union type import for type hinting in linear algebra interface

maths/university/linear_algebra_interface.py

@@ -4,6 +4,7 @@ Gradio Interface for Linear Algebra operations.
 import gradio as gr
 import numpy as np
 import json # For parsing matrices and vectors easily
+from typing import Union
 
 from maths.university.linear_algebra import (
     matrix_add, matrix_subtract, matrix_multiply,