Returns the instance that provides implementation for a registered server. 
   Namespace:   Autodesk.Revit.DB.ExternalService  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 2015.0.0.0 (2015.0.0.0) 
  Since:  2013 
Syntax
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Parameters
- serverId
-  Type:  System Guid  
 Id of a registered server
Return Value
An instance of the server interface. NULL is returned if the server is invalid (e.g. destroyed)Exceptions
| Exception | Condition | 
|---|---|
| Autodesk.Revit.Exceptions ArgumentException | The given Id is not a valid GUID value. |