def METHOD_NAME(self, resource):
    """If the resource added is a DockerDaemon, make sure this is the
    only one added for this target.  If it is, create a docker
    client to be used to communicate with the docker daemon.
    """
    import docker  # lazy import!
    if resource.target.name in self._client:
        raise EnvironmentError(
            "Only one docker daemon is allowed for each target")
    self._client[resource.target.name] = \
        docker.DockerClient(base_url=resource.docker_daemon_url)
    self._container_cleanup(self._client[resource.target.name])
    resource.avail = True