diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ba0430d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+__pycache__/
\ No newline at end of file
diff --git a/SudokuSolver.py b/SudokuSolver.py
index 361d5f8..b456d2b 100644
--- a/SudokuSolver.py
+++ b/SudokuSolver.py
@@ -41,4 +41,15 @@ class SudokuSolver:
                 if grid[box_row + i][box_col + j] == num:
                     return False
 
+        return True
+    
+    @staticmethod
+    def is_valid_solution(grid):
+    # Check if each row, column, and 3x3 box contains all numbers from 1 to 9
+        for i in range(9):
+            row_nums = set(grid[i])
+            col_nums = set(grid[j][i] for j in range(9))
+            box_nums = set(grid[i//3*3+j//3][i%3*3+j%3] for j in range(9))
+            if row_nums != set(range(1, 10)) or col_nums != set(range(1, 10)) or box_nums != set(range(1, 10)):
+                return False
         return True
\ No newline at end of file
diff --git a/tests/test_SudokuSolver.py b/tests/test_SudokuSolver.py
index e797b47..606fc01 100644
--- a/tests/test_SudokuSolver.py
+++ b/tests/test_SudokuSolver.py
@@ -17,7 +17,7 @@ def test_solve_sudoku():
         [0, 0, 0, 0, 8, 0, 0, 7, 9]
     ]
     assert SudokuSolver.solve(grid)
-    assert is_valid_solution(grid)
+    assert SudokuSolver.is_valid_solution(grid)
 
     # Test an invalid Sudoku grid
     grid = [
@@ -33,13 +33,3 @@ def test_solve_sudoku():
     ]
     assert not SudokuSolver.solve(grid)
 
-def is_valid_solution(grid):
-    # Check if each row, column, and 3x3 box contains all numbers from 1 to 9
-    for i in range(9):
-        row_nums = set(grid[i])
-        col_nums = set(grid[j][i] for j in range(9))
-        box_nums = set(grid[i//3*3+j//3][i%3*3+j%3] for j in range(9))
-        if row_nums != set(range(1, 10)) or col_nums != set(range(1, 10)) or box_nums != set(range(1, 10)):
-            return False
-    return True
-