Add the given breathing to the given (possibly accented) character.

def add_breathing(ch, breathing):
    """
    Add the given breathing to the given (possibly accented) character.
    """
    decomposed = unicodedata.normalize("NFD", ch)
    if len(decomposed) > 1 and decomposed[1] == LONG:
        return unicodedata.normalize(
            "NFC", decomposed[0:2] + breathing + decomposed[2:])
    else:
        return unicodedata.normalize(
            "NFC", decomposed[0] + breathing + decomposed[1:])