Qt override.

        Reimplemented from base class to allow the use of custom filtering.

def filterAcceptsRow(self, row_num, parent):
        """Qt override.

        Reimplemented from base class to allow the use of custom filtering.
        """
        model = self.sourceModel()

        # The source model should have a method called row()
        # which returns the table row as a python list.
        tests = [func(model.row(row_num), self._filter_string,
                 self._filter_status) for func in
                 self._filter_functions.values()]

        return False not in tests