union

def _union():
    pass
    """
            # The number of key columns must be equal for any to match.
        if len(base_keys) != len(concat_keys):
            raise ValueError("Length of keys doesn't fit")

        new_base_matrix = []

        base_matrix_obj = ParseVectors(
            file_name=args.base_matrix,
            has_col_names=args.column_titles,
            has_row_names=args.row_titles,
            delimiter=args.delimiter,
            generate_vectors=False
        )
        base_matrix = base_matrix_obj.parse()

        # has_col_names = False, has_row_names = False, delimiter = "\t", generate_vectors = False
        # Handle base matrix column titles.
        # If base matrix has no titles but append matrices do.
        append_titles = None
        if args.column_titles or args.column_titles_2:
            if args.column_titles:
                append_titles = base_matrix_obj.col_titles
            else:
                append_titles = np.array(["None" for i in range(len(base_matrix[0]))])

        for matrix_to_append in args.matrices_to_append:

            mta = ParseVectors(matrix_to_append, args.column_titles_2, args.row_titles_2)
            mta_matrix = mta.parse()

            # Handle column names.
            if args.column_titles or args.column_titles_2:
                if args.column_titles_2:
                    append_titles = np.concatenate((append_titles, mta_matrix.col_titles))
                else:
                    tmp_arr = np.array(["None" for i in range(len(mta_matrix[0]))])
                    append_titles = np.concatenate((append_titles, tmp_arr))

            new_base_matrix = []
            for base_row in base_matrix:
                for append_row in mta_matrix:
                    new_base_matrix.append(np.concatenate((base_row, append_row)))


            # Handle column titles
            if args.column_titles or args.column_titles_2:
                new_base_matrix.insert(0, append_titles)

            base_matrix = np.array(new_base_matrix)
    """
Is this dead code? Do you want to implement something here or can I remove this?
Comments (1)
