def serialize_sign(stream, w):
    s_long(stream, 4)  # version
    s_unicode(stream, w.payload)
    s_unicode(stream, w.caption)
    s_unicode(stream, w.algorithm)
    s_unicode(stream, w.key_name)
    s_unicode(stream, w.index)

def serialize_mydigipass_widget_result(stream, result):
    s_long(stream, 2)  # version
    if result.eid_profile is None:
        s_bool(stream, False)
    else:
        s_bool(stream, True)
        serialize_mydigipass_eid_profile(stream, result.eid_profile)

    if result.eid_address is None:
        s_bool(stream, False)
    else:
        s_bool(stream, True)
        serialize_mydigipass_eid_address(stream, result.eid_address)

    s_unicode(stream, result.eid_photo)
    s_unicode(stream, result.email)
    s_unicode(stream, result.phone)

    if result.profile is None:
        s_bool(stream, False)
    else:
        s_bool(stream, True)
        serialize_mydigipass_profile(stream, result.profile)

    if result.address is None:
        s_bool(stream, False)
    else:
        s_bool(stream, True)
        serialize_mydigipass_address(stream, result.address)

def serialize_form_result(stream, fr):
    s_long(stream, 1)  # version
    if fr:
        s_unicode(stream, fr.type)
        WIDGET_RESULT_MAPPING[fr.type].model_serialize(stream, fr.result)
    else:
        s_unicode(stream, "")

def _serialize_attachment(stream, a):
    s_long(stream, a.index)
    s_unicode(stream, a.content_type)
    s_unicode(stream, a.download_url)
    s_long(stream, a.size)
    s_unicode(stream, a.name)
    _s_thumbnail_url(stream, a.thumbnail)

def _serialize_mobile_details(stream, fds):
    s_long(stream, CURRENT_MOBILE_DETAILS_VERSION)  # version in case we need to adjust the MobileDetail structure
    if fds is None:
        s_bool(stream, False)
    else:
        s_bool(stream, True)
        _serialize_mobile_detail_list(stream, fds.values())

def _serialize_button(stream, b):
    s_unicode(stream, b.id)
    s_long(stream, b.index)
    s_unicode(stream, b.caption)
    s_unicode(stream, b.action)
    s_long(stream, b.ui_flags)
    s_unicode(stream, b.color)

def _serialize_public_keys(stream, public_keys):
    s_long(stream, 1)
    if public_keys is None:
        s_bool(stream, False)
    else:
        s_bool(stream, True)
        _serialize_public_key_list(stream, public_keys.values())

def serialize_location_widget_result(stream, result):
    s_long(stream, 2)  # version
    s_float(stream, result.horizontal_accuracy)
    s_float(stream, result.latitude)
    s_float(stream, result.longitude)
    s_float(stream, result.altitude)
    s_long(stream, result.timestamp)
    s_float(stream, result.vertical_accuracy)

def serialize_pay(stream, w):
    s_long(stream, 2)
    _serialize_payment_method_list(stream, w.methods)
    s_unicode(stream, w.memo)
    s_unicode(stream, w.target)
    s_bool(stream, w.auto_submit)
    s_bool(stream, w.test_mode)
    s_unicode(stream, w.embedded_app_id)

def _serialize_message_embedded_app(stream, obj):
    # type: (StringIO.StringIO, MessageEmbeddedApp) -> None
    s_long(stream, 1)  # version
    s_unicode(stream, obj.context)
    s_unicode(stream, obj.description)
    s_unicode(stream, obj.id)
    s_unicode(stream, obj.image_url)
    s_unicode(stream, obj.result)
    s_unicode(stream, obj.title)

def _serialize_kv_store(stream, kv_store):
    azzert(kv_store is None or isinstance(kv_store._ancestor, db.Key))
    s_long(stream, 1)  # version
    if kv_store:
        s_str(stream, str(kv_store._ancestor))
        _serialize_dict(stream, kv_store._bucket_sizes, s_long, s_long)
        _serialize_dict(stream, kv_store._keys, s_unicode, s_long)
        _serialize_dict(stream, kv_store._blob_keys, s_unicode, s_long_list)
    else:
        s_str(stream, None)

def _serialize_member_status(stream, r):
    s_long(stream, r.status)
    s_long(stream, r.received_timestamp)
    s_long(stream, r.acked_timestamp)
    s_long(stream, r.index)
    s_bool(stream, r.dismissed)
    s_long(stream, r.button_index)
    s_unicode(stream, r.custom_reply)
    serialize_form_result(stream, r.form_result)
    s_unicode(stream, r.ack_device)

def serialize_date_select(stream, w):
    s_long(stream, 1)  # version
    s_bool(stream, w.has_date)
    s_bool(stream, w.has_max_date)
    s_bool(stream, w.has_min_date)
    s_long(stream, w.date)
    s_long(stream, w.max_date)
    s_long(stream, w.min_date)
    s_long(stream, w.minute_interval)
    s_unicode(stream, w.mode)
    s_unicode(stream, w.unit)

def _serialize_advanced_order_item(stream, i):
    s_long(stream, 3)  # version
    s_unicode(stream, i.id)
    s_unicode(stream, i.name)
    s_unicode(stream, i.description)
    s_long(stream, i.value)
    s_unicode(stream, i.unit)
    s_long(stream, i.unit_price)
    s_long(stream, i.step)
    s_unicode(stream, i.step_unit)
    s_long(stream, i.step_unit_conversion)
    s_unicode(stream, i.image_url)
    s_bool(stream, i.has_price)

def serialize_oauth_settings(stream, data):
    s_long(stream, 3)  # version
    if data:
        s_unicode(stream, data.url)
        s_unicode(stream, data.authorize_path)
        s_unicode(stream, data.token_path)
        s_unicode(stream, data.identity_path)
        s_unicode(stream, data.scopes)
        s_unicode(stream, data.client_id)
        s_unicode(stream, data.secret)
        s_unicode(stream, data.domain)
        s_unicode(stream, data.service_identity_email)
        s_unicode(stream, data.public_key)
        s_unicode(stream, data.jwt_audience)
        s_unicode(stream, data.jwt_issuer)
    else:
        s_unicode(stream, None)

def _serialize_friend_detail(stream, fd):
    s_unicode(stream, fd.email)
    s_unicode(stream, fd.name)
    s_long(stream, fd.avatarId)
    s_bool(stream, fd.shareLocation)
    s_bool(stream, fd.sharesLocation)
    s_bool(stream, fd.sharesContacts)
    s_long(stream, fd.type)
    s_bool(stream, fd.hasUserData)
    s_long(stream, fd.relationVersion)
    s_long(stream, fd.existence)

def _serialize_news_item_statistics(stream, stats):
    """
    Args:
        stream (StringIO)
        stats (NewsItemStatistics)
    """
    s_long(stream, 1)  # version
    s_long_list(stream, stats.reached_age)
    s_long_list(stream, stats.reached_gender)
    s_long_list(stream, stats.reached_time)
    s_long_list(stream, stats.rogered_age)
    s_long_list(stream, stats.rogered_gender)
    s_long_list(stream, stats.rogered_time)
    s_long_list(stream, stats.action_age)
    s_long_list(stream, stats.action_gender)
    s_long_list(stream, stats.action_time)
    s_long_list(stream, stats.followed_age)
    s_long_list(stream, stats.followed_gender)
    s_long_list(stream, stats.followed_time)

def _serialize_base_payment_method(stream, c):
    # type: (object, BasePaymentMethod) -> None
    s_long(stream, 2)  # version
    s_bool(stream, c is not None)
    if c:
        s_unicode(stream, c.currency)
        s_long(stream, c.amount)
        s_long(stream, c.precision)

def _serialize_payment_method(stream, c):
    s_long(stream, 2)  # version
    s_unicode(stream, c.provider_id)
    s_unicode(stream, c.currency)
    s_long(stream, c.amount)
    s_long(stream, c.precision)
    s_bool(stream, c.calculate_amount)
    s_unicode(stream, c.target)

def _serialize_news_target_audience(stream, target_audience, version):
    if target_audience:
        s_bool(stream, True)
        s_long(stream, target_audience.min_age)
        s_long(stream, target_audience.max_age)
        s_long(stream, target_audience.gender)
        if version >= 6:
            s_bool(stream, target_audience.connected_users_only)
    else:
        s_bool(stream, False)