Rename lintels using dynamo 2

Hi All

I have a script to rename the lintels so I dont have to do it manually. But not entirely sure what is the problem with this one? Error is

Warning: Element.SetParameterByName operation failed.
The call is ambiguous between the following methods or properties: ‘Revit.Elements.InternalUtilities.ElementUtils.SetParameterValue(Autodesk.Revit.DB.Parameter, Revit.Elements.Element)’ and ‘Revit.Elements.InternalUtilities.ElementUtils.SetParameterValue(Autodesk.Revit.DB.Parameter, string)’

Seems you are feeding null in the Values…