diff --git a/matrix/rotate_matrix.py b/matrix/rotate_matrix.py
index 6daf7e0cf..f638597ae 100644
--- a/matrix/rotate_matrix.py
+++ b/matrix/rotate_matrix.py
@@ -5,8 +5,10 @@ Discussion in stackoverflow:
 https://stackoverflow.com/questions/42519/how-do-you-rotate-a-two-dimensional-array
 """
 
+from __future__ import annotations
 
-def make_matrix(row_size: int = 4) -> [[int]]:
+
+def make_matrix(row_size: int = 4) -> list[list]:
     """
     >>> make_matrix()
     [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]]
@@ -23,7 +25,7 @@ def make_matrix(row_size: int = 4) -> [[int]]:
     return [[1 + x + y * row_size for x in range(row_size)] for y in range(row_size)]
 
 
-def rotate_90(matrix: [[]]) -> [[]]:
+def rotate_90(matrix: list[list]) -> list[list]:
     """
     >>> rotate_90(make_matrix())
     [[4, 8, 12, 16], [3, 7, 11, 15], [2, 6, 10, 14], [1, 5, 9, 13]]
@@ -35,7 +37,7 @@ def rotate_90(matrix: [[]]) -> [[]]:
     # OR.. transpose(reverse_column(matrix))
 
 
-def rotate_180(matrix: [[]]) -> [[]]:
+def rotate_180(matrix: list[list]) -> list[list]:
     """
     >>> rotate_180(make_matrix())
     [[16, 15, 14, 13], [12, 11, 10, 9], [8, 7, 6, 5], [4, 3, 2, 1]]
@@ -47,7 +49,7 @@ def rotate_180(matrix: [[]]) -> [[]]:
     # OR.. reverse_column(reverse_row(matrix))
 
 
-def rotate_270(matrix: [[]]) -> [[]]:
+def rotate_270(matrix: list[list]) -> list[list]:
     """
     >>> rotate_270(make_matrix())
     [[13, 9, 5, 1], [14, 10, 6, 2], [15, 11, 7, 3], [16, 12, 8, 4]]
@@ -59,22 +61,22 @@ def rotate_270(matrix: [[]]) -> [[]]:
     # OR.. transpose(reverse_row(matrix))
 
 
-def transpose(matrix: [[]]) -> [[]]:
+def transpose(matrix: list[list]) -> list[list]:
     matrix[:] = [list(x) for x in zip(*matrix)]
     return matrix
 
 
-def reverse_row(matrix: [[]]) -> [[]]:
+def reverse_row(matrix: list[list]) -> list[list]:
     matrix[:] = matrix[::-1]
     return matrix
 
 
-def reverse_column(matrix: [[]]) -> [[]]:
+def reverse_column(matrix: list[list]) -> list[list]:
     matrix[:] = [x[::-1] for x in matrix]
     return matrix
 
 
-def print_matrix(matrix: [[]]) -> [[]]:
+def print_matrix(matrix: list[list]) -> None:
     for i in matrix:
         print(*i)
 
diff --git a/matrix/tests/test_matrix_operation.py b/matrix/tests/test_matrix_operation.py
index 3500dfeb0..65b35fd7e 100644
--- a/matrix/tests/test_matrix_operation.py
+++ b/matrix/tests/test_matrix_operation.py
@@ -12,7 +12,7 @@ import logging
 import sys
 
 import numpy as np
-import pytest
+import pytest  # type: ignore
 
 # Custom/local libraries
 from matrix import matrix_operation as matop