def format_chars(chars_sent_ls):
    max_leng = max([len(l) for l in chars_sent_ls])
    to_pads = [max_leng - len(l) for l in chars_sent_ls]
    for i, to_pad in enumerate(to_pads):
        if to_pad % 2 == 0:
            chars_sent_ls[i] = [0] * (to_pad / 2) + chars_sent_ls[i] + [0] * (to_pad / 2)
        else:
            chars_sent_ls[i] = [0] * (1 + (to_pad / 2)) + chars_sent_ls[i] + [0] * (to_pad / 2)
    return chars_sent_ls