tr_iter(text, kword, color)

def tr_iter(text, kword, color):
    """ tr_iter(text, kword, color)
    """
    s=''
    for _t in text:
        if _t in kword:
            s += colorize(BgColor.Null, Base.Null, color, _t)
        else:
            s += _t
    return s