python imap utf7

# based on: http://www.php2python.com/wiki/function.imap-utf7-encode/

def modified_base64(s):
    s_utf7 = s.encode('utf-7')  # 
    aaa = s_utf7[1:-1].decode().replace('/', ',')  # rfc2060
    return aaa


def modified_unbase64(s):
    s_utf7 = '+' + s.replace(',', '/') + '-'
    return s_utf7.encode().decode('utf-7')

def encode_imap4_utf7(s, errors=None):
    r = list()
    _in = list()
    for c in s:
        if ord(c) in range(0x20, 0x25) or ord(c) in range(0x27, 0x7e):
            if _in:
                r.extend(['&', modified_base64(''.join(_in)), '-'])
                del _in[:]
            r.append(str(c))
        elif ord(c) == 0x26:  # символ &
            if _in:
                r.extend(['&', modified_base64(''.join(_in)), '-'])
                del _in[:]
            r.append('&-')
        else:
            _in.append(c)
    if _in:
        r.extend(['&', modified_base64(''.join(_in)), '-'])
    return ''.join(r), len(s)

def decode_imap4_utf7(s):
    r = list()
    if s.find('&-') != -1:
        s = s.split('&-')
        i = len(s)
        for subs in s:
            i -= 1
            r.append(decode_imap4_utf7(subs))
            if i != 0:
                r.append('&')
    else:
        # шаблон для строки символов, экранированных & - (т.е. то, что надо декодировать)
        regex = re.compile(r'[&]\S+?[-]')
        sym = re.split(regex, s)
        # если подстрок много
        if len(regex.findall(s)) > 1:
            i = 0
            r.append(sym[i])
            for subs in regex.findall(s):
                r.append(decode_imap4_utf7(subs))
                i += 1
                r.append(sym[i])
        # только 1 подстрока
        elif len(regex.findall(s)) == 1:
            r.append(sym[0])
            r.append(modified_unbase64(regex.findall(s)[0][1:-1]))
            r.append(sym[1])
        # ничего декодировать не надо
        else:
            r.append(s)
    return ''.join(r)

status, folders = mailbox.list()
for item in folders:
    print(decode_imap4_utf7(item.decode()))
print(mailbox.select(encode_imap4_utf7('"[Gmail]/Вся почта"')[0]))