I am using docker for windows which runs the docker daemon inside a Hyper-V VM.
This library is used inside a docker container and for authentication purposes the corresponding port is exposed to my machine. This way I can access the launched WSGI server on localhost on my machine, however the server inside the docker container does only listen on the ip behind localhost resolved within the container -> You do not receive an answer for localhost on your machine, only within the container (e.g. with curl)
This could easily be mitigated by passing an empty String as host parameter to the Flow.run_local_server function, but this will raise an error because the redirect url is equal to the chosen host string -> empty URL is not possible

As a solution the function could be extended by an optional parameter redirect_host that defaults to the value of host and is inserted into the redirect_host variable.