edited challenge notebook and added tests

arrays_strings/group_items/group_ordered.py

@@ -0,0 +1,26 @@
+def make_order_list(list_in):
+    order_list = []
+    for item in list_in:
+        if item not in order_list:
+            order_list.append(item)
+    return order_list
+
+
+def group_ordered(list_in):
+    if list_in is None:
+        return None
+    order_list = make_order_list(list_in)
+    current = 0
+    for item in order_list:
+        search = current + 1
+        while True:
+            try:
+                if list_in[search] != item:
+                    search += 1
+                else:
+                    current += 1
+                    list_in[current], list_in[search] = list_in[search], list_in[current]
+                    search += 1
+            except IndexError:
+                break
+    return list_in