ID 227323 - Session.registerFunction doesn't call when executed via the GUI

Problem summary
quick summary of the problem

Customer reported version

3.0v3

Customer reported platform
rhel6

Steps to reproduce

1) Launch Mari, open up a project e.g. the example head (Go to Help>Create Example Project)

2) Open up the script editor

3) Run the following code:
 

import mari

def imDone():

print "Mr Post Function"

#registerFunction allows us to attach something to do after exporting a session is finished

mari.session.registerFunction("postExport", imDone)

mari.session.exportSession("/Users/nopass/tdata/test")

4) evaluate 'imDone' within the script editor, a message should appear

5) Now export a session and notice that postExport doesn't appear to evaluate when you export a Mari Session 

Reproduced by support
Fedora Schrodinger's Cat
Windows 7
Mac OSX 10.11 El Capitan

3.0v3, 3.0v4 and 3.1v1

Expected behaviour
for postExport to evaluate and fire off a message when a session was created

Actual behaviour
postExport did not evaluate