Hello @somphon
you have a conflict between 2 namespaces (Revit API , and Dynamo Proto API)
remove this if you don’t use it
clr.AddReference('ProtoGeometry')
from Autodesk.DesignScript.Geometry import *
or use an alias
clr.AddReference('RevitAPI')
from Autodesk.Revit.DB import *
import Autodesk.Revit.DB as DB
#.... // ...
Line1 = DB.Line.CreateBound(pt1, pt2)