def decode(encoded_str):
    ''' Decode Base91 string to a bytearray '''
    v = -1
    b = 0
    n = 0
    out = bytearray()
    for strletter in encoded_str:
        if not strletter in decode_table:
            continue
        c = decode_table[strletter]
        if(v < 0):
            v = c
        else:
            v += c*91
            b |= v << n
            n += 13 if (v & 8191)>88 else 14
            while True:
                out += struct.pack('B', b&255)
                b >>= 8
                n -= 8
                if not n>7:
                    break
            v = -1
    if v+1:
        out += struct.pack('B', (b | v << n) & 255 )
    return out