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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def filterAcceptsRow(self, row, parentindex):
 """Return True, if the filter accepts the given row of the parent :param row: the row to filter :type row: :class:`int` :param parentindex: the parent index :type parentindex: :class:`QtCore.QModelIndex` :returns: True, if the filter accepts the row :rtype: :class:`bool` :raises: None """

        if not super(ReftrackSortFilterModel, self).filterAcceptsRow(row, parentindex):
            return False
        if parentindex.isValid():
            m = parentindex.model()
        else:
            m = self.sourceModel()

        i = m.index(row, 18, parentindex)
        reftrack = i.data(REFTRACK_OBJECT_ROLE)
        if not reftrack:
            return True
        else:
            return self.filter_accept_reftrack(reftrack)