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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(self, column_name, default=None):
 """ Return the Datum for column_name, or default. """

        if column_name in self.table.default_columns:
            index = self.table.default_columns.index(column_name)
            return Datum(self.cells[index], self.row_num, column_name, self.table)
        return default