When trying to attach a WebSocket, a {ValueError} scheme http+docker is invalid raised.
Using docker-py==2.1, websocket-client==0.40.0, docker 1.12.5.
Executing the following before/after container run command brings out the same result. The Code used to attach a new WebSocket is as follows:

sock = self.client.api.attach_socket(self.container_id, params={ 'origin': 'http://127.0.0.1:4502' }, ws=True)

The Exception is actually raised from the websocket.create_connection function. This is the URL passed to the create_connection function (generated by docker-py):
http+docker://localunixsocket/v1.24/containers/50aa7d8e10a0a15ffc659e754ebfbe230981dde16d739b53d729d20fea8c1c41/attach/ws?origin=http%3A%2F%2F127.0.0.1%3A4502

Is this a bug or miss-usage? I've gone over the tests and there does't seem to be an attach_socket test that uses websocket.