Transferring a CSV file to a database while merging some columns
csv.DictReader accepts 'restKey' 3rd parameter.  

with open(data_filename) as f, sqlite3.connect(db_filename) as conn:
        conn.executescript(SQL_create_table)
        cursor = conn.cursor()
        next(f, None)      # Skip the headers
        reader_object = csv.DictReader(f,['important1','important2'],'item_list')
        row_count = 0
        for row_dict in reader_object:
            row_count += 1
            row_dict['item_list'] = repr(row_dict['item_list'])  # convert list to string first
            cursor.execute(SQL, row_dict)