private void checkVirtualNetworkSite(VirtualNetworkSite virtualNetworkSite) {
   assertNotNull(virtualNetworkSite.name(), "Name cannot be null for a VirtualNetworkSite.");
   assertNotNull(
       virtualNetworkSite.addressSpace(),
       "AddressSpace cannot be null for: " + virtualNetworkSite);
   assertNotNull(
       virtualNetworkSite.subnets(), "Subnets cannot be null for: " + virtualNetworkSite);
 }
 @Test
 public void testGetNetworkConfiguration() {
   final NetworkConfiguration networkConfiguration = api().getNetworkConfiguration();
   assertThat(networkConfiguration).isNotNull();
   for (VirtualNetworkSite vns :
       networkConfiguration.virtualNetworkConfiguration().virtualNetworkSites()) {
     assertThat(vns.name()).isNotEqualTo("not-existing");
   }
 }