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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 _get_aliased_pivot_columns(self):
 """ Get the pivot columns for the relation. :rtype: list """

        defaults = [self._foreign_key, self._other_key]

        columns = []

        for column in defaults + self._pivot_columns:
            value = '%s.%s AS pivot_%s' % (self._table, column, column)
            if value not in columns:
                columns.append('%s.%s AS pivot_%s' % (self._table, column, column))

        return columns