docs: @POST
      @Path("/importer")
      @Consumes(MediaType.MULTIPART_FORM_DATA)
      @Produces(MediaType.APPLICATION_JSON)
      public Response importDevice(
              @MultipartForm
              ImporterForm form,
              @Context HttpServletRequest request) {
  
          // find the matching variation:
          final Variant variant = loadVariantWhenAuthorized(request);
          if (variant == null) {
              return create401Response(request);
          }
  
          List<Installation> devices;
          try {
              devices = mapper.readValue(form.getJsonFile(), new TypeReference<List<Installation>>() {});
          } catch (IOException e) {
              logger.error("Error when parsing importer json file", e);
  
              return Response.status(Status.BAD_REQUEST).build();
          }
  
          logger.info("Devices to import: {}", devices.size());
  
          clientInstallationService.addInstallations(variant, devices);
  
          // return directly, the above is async and may take a bit :-)
          return Response.ok(EmptyJSON.STRING).build();
      }