def prepare_table_rows(rows):
    """Given a list of lists, make sure they are prepared to be formatted into a table
    by making sure each row has the same number of columns and stringifying all values."""
    rows = [list(map(str, r)) for r in rows]
    max_cols = max(list(map(len, rows)))
    for row in rows:
        pad = max_cols - len(row)
        for _ in range(pad):
            row.append('')
    return rows