77-2 in Python 3

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diff --git a/challenge-077/ash/python/ch-2.py b/challenge-077/ash/python/ch-2.py
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+# Task 2 from
+# https://perlweeklychallenge.org/blog/perl-weekly-challenge-077/
+
+# Comments: https://andrewshitov.com/2020/09/08/lonely-x-the-weekly-challenge-77-task-2/
+
+# Output for the given example:
+#
+# $ python3 ch-2.py
+# Lonely X at position (0, 0).
+# Lonely X at position (2, 1).
+# Lonely X at position (0, 2).
+
+matrix = [
+    ['X', 'O', 'O'],
+    ['O', 'O', 'X'],
+    ['X', 'O', 'O'],
+]
+
+def is_O_cell(x, y):
+    if 0 <= x < len(matrix[0]) and 0 <= y < len(matrix):
+        return matrix[y][x] == 'O'
+    else:
+        return True
+
+x_cells = [
+    [col_i, row_i]
+        for row_i, row in enumerate(matrix) 
+            for col_i, cell in enumerate(row)
+    if cell == 'X'
+]
+
+for x_cell in x_cells:
+    x, y = x_cell
+    if is_O_cell(x    , y + 1) and \
+       is_O_cell(x    , y - 1) and \
+       is_O_cell(x + 1, y    ) and \
+       is_O_cell(x - 1, y    ) and \
+       is_O_cell(x + 1, y + 1) and \
+       is_O_cell(x + 1, y - 1) and \
+       is_O_cell(x - 1, y + 1) and \
+       is_O_cell(x - 1, y - 1):
+        print(f"Lonely X at position ({x}, {y}).")