def commas_to_cedillas(text):
    """
    Convert s and t with commas (ș and ț) to cedillas (ş and ţ), which is
    preferred in Turkish.

    Only the lowercase versions are replaced, because this assumes the
    text has already been case-folded.
    """
    return text.replace(
        '\N{LATIN SMALL LETTER S WITH COMMA BELOW}',
        '\N{LATIN SMALL LETTER S WITH CEDILLA}'
    ).replace(
        '\N{LATIN SMALL LETTER T WITH COMMA BELOW}',
        '\N{LATIN SMALL LETTER T WITH CEDILLA}'
    )