Extends the multistory stairs by connecting input levels. 
   Namespace:   Autodesk.Revit.DB.Architecture  
  Assembly:   RevitAPI  (in RevitAPI.dll) Version: 18.0.0.0 (18.2.0.0) 
  Since:  2018 
Syntax
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Parameters
- levelIds
-  Type:  System.Collections.Generic ISet   ElementId  
 The level ids.
Remarks
 The added stairs will be categorized into different groups based on level heights automatically. Stairs with the same level height are considered a group and can be edited together. You cannot connect the levels between standard stairs top and bottom or already connected. 
 Exceptions
| Exception | Condition | 
|---|---|
| Autodesk.Revit.Exceptions ArgumentException | This multistory stairs cannot connect to one or more members of levelIds. | 
| Autodesk.Revit.Exceptions ArgumentNullException | A non-optional argument was NULL |