'Get the partition for an account/container/object.
:param account: account name
:param container: container name
:param obj: object name
:returns: the partition number'

def get_part(self, account, container=None, obj=None):

    key = hash_path(account, container, obj, raw_digest=True)
    if (time() > self._rtime):
        self._reload()
    part = (struct.unpack_from('>I', key)[0] >> self._part_shift)
    return part
