/// <summary>
 /// Gets the list of vBridges for the specified VTN from ODL.
 /// </summary>
 /// <param name="vtnName">Name of the VTN.</param>
 /// <returns>List of vBridges.</returns>
 public List<string> GetVbridgesListforVtn(string vtnName)
 {
     Controller odl = new Controller(this.ConnectionString, this.Credential);
     ODLVSEMETW.EventWriteReturnODLLibrary("Return from ODL Library.", string.Empty);
     List<string> existingVtns = odl.GetVbridgesListforVtn(vtnName);
     return existingVtns;
 }