'Parse an association as stored by serialize().
inverse of serialize
@param assoc_s: Association as serialized by serialize()
@type assoc_s: str
@return: instance of this class'

def deserialize(cls, assoc_s):

    pairs = kvform.kvToSeq(assoc_s, strict=True)
    keys = []
    values = []
    for (k, v) in pairs:
        keys.append(k)
        values.append(v)
    if (keys != cls.assoc_keys):
        raise ValueError('Unexpected    key    values:    %r', keys)
    (version, handle, secret, issued, lifetime, assoc_type) = values
    if (version != '2'):
        raise ValueError(('Unknown    version:    %r' % version))
    issued = int(issued)
    lifetime = int(lifetime)
    secret = oidutil.fromBase64(secret)
    return cls(handle, secret, issued, lifetime, assoc_type)
