fix generator and range

src/common/helpers.py

@@ -951,7 +951,7 @@ def get_random_string_16():
     """
     Create random string of length 16
     """
-    rng = range(65, 90)
+    rng = list(range(65, 90))
     rng.extend(range(48, 57))
     char_sequence = [chr(e) for e in rng]
     from random import sample

src/roster_window.py

@@ -1415,7 +1415,7 @@ class RosterWindow:
             yield False
 
         task = _draw_all_contacts(jids, account)
-        GObject.idle_add(task.next)
+        GObject.idle_add(next, task)
 
     def _before_fill(self):
         self.tree.freeze_child_notify()