get RevitLinkInstance dynamo revit
import clr
clr.AddReference('RevitAPI')
import Autodesk
from Autodesk.Revit.DB import *
from Autodesk.Revit.Attributes import*
clr.AddReference("RevitServices")
import RevitServices
from RevitServices.Persistence import DocumentManager
from RevitServices.Transactions import TransactionManager
clr.AddReference("RevitNodes")
import Revit
clr.ImportExtensions(Revit.Elements)
dataEnteringNode = IN
doc = DocumentManager.Instance.CurrentDBDocument
revitlinktypes=list()
linkcollector=FilteredElementCollector(doc).OfClass(RevitLinkInstance)
revitlinktypes=[]
TransactionManager.Instance.ForceCloseTransaction()
for rli in linkcollector:
rlt=doc.GetElement(rli.GetTypeId())
revitlinktypes.append(rlt)
rlt.Unload(None)
OUT= 0