Problem with packing/unpacking tuples which is big obstacle in complex structures #202

import msgpack

class Period(object):
    def __init__(self, key):
        self.key = key

    def __hash__(self):
        return hash(self.key)

    def __eq__(self, other):
        self.key == self.key

def encode(o):
    if type(o) is Period:
        return msgpack.ExtType(0, msgpack.dumps(o.__dict__))

def decode_ext(code, data):
    if code == 0:
        o = Period.__new__(Period)
        o.__dict__ = msgpack.loads(data)
        return o

o = {Period((2016, 7)): 112, Period((2016, 8)): 231}

print o
s = msgpack.dumps(o, default=encode)
print s
o2 = msgpack.loads(s, ext_hook=decode_ext)
print o2

C:\root\Python27-64\python.exe "C:/Users/Cezary Wagner/PycharmProjects/msgpack_learn/src/02_tuple_wrong_pack.py"
Traceback (most recent call last):
{<__main__.Period object at 0x0000000002941668>: 231, <__main__.Period object at 0x0000000002941AC8>: 112}
  File "C:/Users/Cezary Wagner/PycharmProjects/msgpack_learn/src/02_tuple_wrong_pack.py", line 28, in <module>
��
    o2 = msgpack.loads(s, ext_hook=decode_ext)
 ��key��������
  File "msgpack/_unpacker.pyx", line 139, in msgpack._unpacker.unpackb (msgpack/_unpacker.cpp:139)
 ��key�����p
  File "C:/Users/Cezary Wagner/PycharmProjects/msgpack_learn/src/02_tuple_wrong_pack.py", line 8, in __hash__
    return hash(self.key)
TypeError: unhashable type: 'list'

Process finished with exit code 1