def get_prefix(headword, length):
    if headword is None:
        return None
    lowercased = headword.lower()
    if ord(lowercased[0]) < 97:
        return u"SPECIAL"
    if len(lowercased) < length:
        return lowercased
    return lowercased[0:length]
Return the prefix for the given headword,
dataset/ETHPy150Open pettarin/penelope/penelope/prefix_default.py/get_prefix