/// <summary>
 /// Get or create new ubuntu server 16.04 LTS vm in a resource group.
 /// </summary>
 /// <param name="service"></param>
 /// <param name="resourceGroup"></param>
 /// <param name="name"></param>
 /// <param name="network"></param>
 /// <returns></returns>
 public static Task <IVirtualMachineResource> GetOrCreateBionicAsync(
     this IVirtualMachineFactory service, IResourceGroupResource resourceGroup,
     string name, INetworkResource network = null) =>
 service.GetOrCreateAsync(resourceGroup, name, network, KnownImages.Ubuntu_18_04_lts);
 /// <summary>
 /// Get or create new ubuntu server 16.04 LTS vm in a resource group.
 /// </summary>
 /// <param name="service"></param>
 /// <param name="resourceGroup"></param>
 /// <param name="name"></param>
 /// <param name="network"></param>
 /// <returns></returns>
 public static Task <IVirtualMachineResource> GetOrCreateXenialAsync(
     this IVirtualMachineFactory service, IResourceGroupResource resourceGroup,
     string name, INetworkResource network = null)
 {
     return(service.GetOrCreateAsync(resourceGroup, name, network, KnownImages.Ubuntu_16_04_lts));
 }