Index: pypet-0.6.1/pypet/storageservice.py
===================================================================
--- pypet-0.6.1.orig/pypet/storageservice.py
+++ pypet-0.6.1/pypet/storageservice.py
@@ -3175,7 +3175,8 @@ class HDF5StorageService(StorageService,
                     # in the list or tuple
                     for idx, item in enumerate(data):
                         if typestr == str.__name__:
-                            data[idx] = data[idx].decode(self._encoding)
+                            if hasattr(data[idx], "decode"):
+                                data[idx] = data[idx].decode(self._encoding)
                         else:
                             try:
                                 data[idx] = pypetconstants.PARAMETERTYPEDICT[typestr](item)