def convert_rows_list_to_csv_str(rows_list):
sep = os.linesep<EOL>expected = sep.join(rows_list) + sep<EOL>return expected<EOL>
Convert list of CSV rows to single CSV-formatted string for current OS.

This method is used for creating expected value of to_csv() method.

Parameters
----------
rows_list : list
    The list of string. Each element represents the row of csv.

Returns
-------
expected : string
    Expected output of to_csv() in current OS