Update n_queens.py

Author: MaximSmolskiy

backtracking/n_queens.py

@@ -27,8 +27,12 @@ def is_safe(board: list[list[int]], row: int, column: int) -> bool:
 
     >>> is_safe([[0, 0, 0], [0, 0, 0], [0, 0, 0]], 1, 1)
     True
+    >>> is_safe([[0, 1, 0], [0, 0, 0], [0, 0, 0]], 1, 1)
+    False
     >>> is_safe([[1, 0, 0], [0, 0, 0], [0, 0, 0]], 1, 1)
     False
+    >>> is_safe([[0, 0, 1], [0, 0, 0], [0, 0, 0]], 1, 1)
+    False
     """
 
     n = len(board)  # Size of the board