get document

get document：

import clr
# Import DocumentManager
clr.AddReference("RevitServices")
import RevitServices
from RevitServices.Persistence import DocumentManager

doc = DocumentManager.Instance.CurrentDBDocument
uiapp = DocumentManager.Instance.CurrentUIApplication
app = uiapp.Application

#Assign your output to the OUT variable
#OUT is defined as a list of three items
OUT=[doc,uiapp,app]