open document file dynamo revit
import clr
clr.AddReference('RevitServices')
import RevitServices
from RevitServices.Persistence import DocumentManager
clr.AddReference('RevitAPI')
import Autodesk
from Autodesk.Revit.DB import *
doc = DocumentManager.Instance.CurrentDBDocument
app = doc.Application
filePath = IN[0]
modelPath = ModelPathUtils.ConvertUserVisiblePathToModelPath(filePath)
options = OpenOptions()
options.DetachFromCentralOption = DetachFromCentralOption.DetachAndPreserveWorksets
docOnDisk = app.OpenDocumentFile(modelPath, options)
OUT = docOnDisk