UnboundLocalError exception

gistfile1.txt

freeseer/tests/framework/database/test_database.py:104: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <freeseer.framework.database.QtDBConnector object at 0x7f7d4c743110>, fname = ''

    def export_talks_to_csv(self, fname):
        fieldNames = ('Title',
                      'Speaker',
                      'Abstract',
                      'Category',
                      'Event',
                      'Room',
                      'Date',
                      'StartTime',
                      'EndTime')
    
        try:
            file = open(fname, 'w')
            writer = csv.DictWriter(file, fieldnames=fieldNames)
            headers = dict((n, n) for n in fieldNames)
            writer.writerow(headers)
    
            result = self.get_talks()
            while result.next():
                log.debug(unicode(result.value(1).toString()))
                writer.writerow({'Title': unicode(result.value(1).toString()),
                                 'Speaker': unicode(result.value(2).toString()),
                                 'Abstract': unicode(result.value(3).toString()),
                                 'Category': unicode(result.value(4).toString()),
                                 'Event': unicode(result.value(5).toString()),
                                 'Room': unicode(result.value(6).toString()),
                                 'Date': unicode(result.value(7).toString()),
                                 'StartTime': unicode(result.value(8).toString()),
                                 'EndTime': unicode(result.value(9).toString())})
        finally:
>           file.close()
E           UnboundLocalError: local variable 'file' referenced before assignment