Hi,Couple ideas:1. Itself is one word.2. Double-quotation marks?3. How about tuples? Something like,a = "a", "b", "c", "d", "e",The above becomes an immutable tuple by the compiler. In general, tuplesshould perform a little better than lists, at least in terms of memoryusage.4. This is confusing. Why use x twice?Matrix = [[0 for x in range(5)] for x in range(5)]Use an underscore if the index isn't needed.Matrix = [[0 for _ in range(5)] for _ in range(5)]5. It's okay to put comments above the expression being referred to. Noneed for inline comments in most places.No -print(Matrix[0][0]) # prints 1Yes -# out: 1print(Matrix[0][0])6. Good to check if exists first.Current -def column(matrix, i): return [row[i] for row in matrix]Suggested -def column(matrix, i): if len(matrix) == 0 or len(matrix[0]) >= i: return return [row[i] for row in matrix]Etc.Really, just a terrible file that could use a lot more improvement. Sorryif that comes across as rough as it's not a personal attack.Best,Mark M.