def _quick_and_dirty_glyph_is_empty(font, glyph_name):
    """
    This is meant to be a quick-and-dirty test to see if a glyph is empty.
    Ideally we'd use the glyph_has_ink() method for this, but for a family of
    large CJK CFF fonts with tens of thousands of glyphs each, it's too slow.

    Caveat Utilitor:
    If this method returns True, the glyph is definitely empty.
    If this method returns False, the glyph *might* still be empty.
    """
    if 'glyf' in font:
        glyph = font['glyf'][glyph_name]
        if not glyph.isComposite():
            if glyph.numberOfContours == 0:
                return True
        return False
    elif 'CFF2' in font:
        top_dict = font['CFF2'].cff.topDictIndex[0]
    else:
        top_dict = font['CFF '].cff.topDictIndex[0]
    char_strings = top_dict.CharStrings
    char_string = char_strings[glyph_name]
    if len(char_string.bytecode) <= 1:
        return True
    return False
