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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 add(self, left_column, right_column, indexes=None):
 """ Math helper method that adds element-wise two columns. If indexes are not None then will only perform the math on that sub-set of the columns. :param left_column: first column name :param right_column: second column name :param indexes: list of index values or list of booleans. If a list of booleans then the list must be the same\ length as the DataFrame :return: list """

        left_list, right_list = self._get_lists(left_column, right_column, indexes)
        return [l + r for l, r in zip(left_list, right_list)]