def __init__(<EOL>self,<EOL>input_columns: t.List[Column],<EOL>output_columns: t.List[Column],<EOL>column_transform,) -> None:
self.input_columns = input_columns<EOL>self.output_columns = output_columns<EOL>self.column_transform = column_transform<EOL>
Construct a new ``CompoundColumn`` object.

        Args:
            input_columns (list, Column): A list of ``Column`` objects representing column(s) from the SOURCE table.
            output_columns (list, Column): A list of ``Column`` objects representing column(s) from the FINAL table.
            column_transform (Callable): Function accepting the table object, performing transformations to it and returning a DataFrame containing the NEW columns only.