diff -r ed6b0e905fcb -r 8742337a9fe3 runtime/Worker.py
--- a/runtime/Worker.py	Tue Nov 27 13:34:14 2018 +0100
+++ b/runtime/Worker.py	Tue Dec 04 11:31:58 2018 +0100
@@ -9,6 +9,7 @@
 
 from __future__ import absolute_import
 import sys
+import six
 import thread
 from threading import Lock, Condition