Fixed error when a document has multiple "main" objects

ahb_techdraw_extensions.py

@@ -800,9 +800,9 @@ class TechDrawExtensions:
 					if obj.TypeId == 'TechDraw::DrawPage':
 						self.onPageLoaded(obj)
 			
-				main_part = doc.getObjectsByLabel(doc.Name)
-				if len(main_part) == 1:
-					main_part = main_part[0]
+				main_parts = doc.getObjectsByLabel(doc.Name)
+				if len(main_parts) == 1:
+					main_part = main_parts[0]
 			except:
 				pass