Crash with undefined 'Mergedinto'

[scamille]

I was trying to migrate http://code.google.com/p/simulationcraft/ to Github.

http://code.google.com/p/simulationcraft/issues/detail?id=100 has a "Mergedinto: -" flag/status, where I assume that the Issue number it originally pointed at got lost.

Now google-code-issues-migrator runs into a problem on line 117/118:

if comment.updates.mergedIntoUpdate:
        return "_This issue is a duplicate of #%d_" % (options.base_id + int(comment.updates.mergedIntoUpdate.text))

Traceback:

File "migrateissues.py", line 118, in format_comment
    return "_This issue is a duplicate of #%d_" % (options.base_id + int(comment.updates.mergedIntoUpdate.text))
ValueError: invalid literal for int() with base 10: '-'

When trying to convert the false Mergedinto Number to int.

I've no Python experience at all, otherwise I try solving it myself. But I hope the problem-description is detailed enough.