Just another update

Task/Flatten-a-list/Python/flatten-a-list-1.py

@@ -1,7 +1,11 @@
->>> def flatten(lst):
-	return sum( ([x] if not isinstance(x, list) else flatten(x)
-		     for x in lst), [] )
+>>> def flatten(lst, results=[]):      # 'results' defaults to an empty list []
+        for e in lst:                  #   for each element 'e' in lst
+            if type(e) is list:        #      if that element is a list, then
+                flatten(e, results)    #         flatten that sublist, appending results to "results"
+            else:                      #      if element is not a list, then
+                results.append(e)      #         insert a copy of it at the end of "results"
+        return results
 
->>> lst = [[1], 2, [[3,4], 5], [[[]]], [[[6]]], 7, 8, []]
->>> flatten(lst)
+>>> l = [[1], 2, [[3,4], 5], [[[]]], [[[6]]], 7, 8, []]
+>>> flatten(l)
 [1, 2, 3, 4, 5, 6, 7, 8]

Task/Flatten-a-list/Python/flatten-a-list-3.py

@@ -7,6 +7,6 @@
              yield x
 
 
->>>lst = [[1], 2, [[3,4], 5], [[[]]], [[[6]]], 7, 8, []]
->>>print list(flatten(lst))
+>>> lst = [[1], 2, [[3,4], 5], [[[]]], [[[6]]], 7, 8, []]
+>>> print list(flatten(lst))
 [1, 2, 3, 4, 5, 6, 7, 8]