How to use the rx-jupyter.kernelspecs.list function in rx-jupyter

switchMap((action: LIST_KERNELSPECS) => {
      const host = store.getState().app.host;
      // Normalizing to match rx-jupyter vs. host record
      const serverConfig = {
        endpoint: host.serverUrl,
        token: host.token,
        crossDomain: false
      };

      // $FlowFixMe: WTF
      return kernelspecs.list(serverConfig).pipe(
        tap(xhr => {
          if (xhr.status !== 200) {
            throw new Error(xhr.response);
          }
        }),
        map(xhr => {
          return {
            type: "KERNELSPECS_LISTED",
            payload: xhr.response
          };
        }),
        catchError((xhrError: any) => of(genericAjaxFail(xhrError)))
      );
    })
  );

mergeMap((action: FetchKernelspecs) => {
      const {
        payload: { hostRef, kernelspecsRef }
      } = action;
      const state = store.getState();

      const host = selectors.currentHost(state);
      if (host.type !== "jupyter") {
        // Dismiss any usage that isn't targeting a jupyter server
        return empty();
      }
      const serverConfig = selectors.serverConfig(host);

      return kernelspecs.list(serverConfig).pipe(
        map(data => {
          const defaultKernelName = data.response.default;
          const kernelspecs = {};
          Object.keys(data.response.kernelspecs).forEach(key => {
            const value = data.response.kernelspecs[key];
            kernelspecs[key] = {
              name: value.name,
              resources: value.resources,
              argv: value.spec.argv,
              displayName: value.spec.display_name,
              env: value.spec.env,
              interruptMode: value.spec.interrupt_mode,
              language: value.spec.language,
              metadata: value.spec.metadata
            };
          });

mergeMap((action: actions.FetchKernelspecs) => {
      const {
        payload: { hostRef, kernelspecsRef }
      } = action;
      const state = state$.value;

      const host = selectors.currentHost(state);
      if (host.type !== "jupyter") {
        // Dismiss any usage that isn't targeting a jupyter server
        return empty();
      }
      const serverConfig: ServerConfig = selectors.serverConfig(host);

      return kernelspecs.list(serverConfig).pipe(
        map(data => {
          const defaultKernelName = data.response.default;
          const kernelspecs: { [key: string]: KernelspecProps } = {};
          Object.keys(data.response.kernelspecs).forEach(key => {
            const value = data.response.kernelspecs[key];
            kernelspecs[key] = {
              name: value.name,
              resources: value.resources,
              argv: value.spec.argv,
              displayName: value.spec.display_name,
              env: value.spec.env,
              interruptMode: value.spec.interrupt_mode,
              language: value.spec.language,
              metadata: value.spec.metadata
            };
          });

mergeMap(({ payload: { serverId } }) => {
      const { config } = state$.value.entities.serversById[serverId].server;
      return kernelspecs.list(config).pipe(
        mergeMap(data => {
          const kernelName = data.response.default;
          return of(
            actions.fetchKernelSpecsFulfilled({
              serverId,
              response: data.response
            }),
            actions.setActiveKernel({ serverId, kernelName })
          );
        }),
        catchError(error =>
          of(actions.fetchKernelSpecsFailed({ serverId, error }))
        )
      );
    })
  );