Comment 3 for bug 1625579

http://developer.openstack.org/sdks/python/openstacksdk/users/resources/network/v2/port.html#openstack.network.v2.port.Port

there is definitely a param called "binding_vnic_type".
you can see the api request to create port it transform "binding_vnic_type" to "binding:vnic_type" but does not remove "binding_vnic_type" from the request.