public Map<String, String> getDevicesForClient(Client client) {
   ResponseWrapper response =
       apiService.sendRequest(
           templateGetCustomPropertyByName,
           new HashMap<String, String>() {
             {
               put("customerId", client.getCustomerId());
               put("propertyName", PROPERTY_NAME);
             }
           },
           serviceAddressCustomer);
   String propertyValue = response.getStringAttribute(GetCustomPropertyByName.PROPERTY_VALUE);
   return deserialiseDeviceRegistrations(propertyValue);
 }
 void setDevicesForClient(Client client, Map<String, String> deviceRegistrations) {
   String propertyValue = serialiseDeviceRegistrations(deviceRegistrations);
   try {
     apiService.sendRequest(
         templateSetCustomProperty,
         new HashMap<String, String>() {
           {
             put("customerId", client.getCustomerId());
             put("propertyName", PROPERTY_NAME);
             put("propertyValue", propertyValue);
           }
         },
         serviceAddressCustomer);
   } catch (ApiResponseNotSuccessfulException e) {
     LOG.warn("Could not update device registrations for client due to API error");
   }
 }