new_contents: def set_prior_nodes_from_collection_set(node_obj):
  	print "\n Name : ", node_obj.name, " -- ", node_obj.member_of_names_list , " --- ", node_obj._id
  	if node_obj.collection_set:
  		for each in node_obj.collection_set:
  			each_obj = node_collection.one({'_id': ObjectId(each)})
  			# if "Page" in each_obj.member_of_names_list:
  			# 	print "\n\n Page -- ", each_obj.prior_node
  			if node_obj._id not in each_obj.prior_node:
  				each_obj.prior_node.append(node_obj._id)
  				each_obj.save()
  			set_prior_nodes_from_collection_set(each_obj)
  
  ce_gst = node_collection.one({'_type': "GSystemType", 'name': "CourseEventGroup"})
  course_event_grps = node_collection.find({'member_of': ce_gst._id})
  
  for eachce in course_event_grps:
  	set_prior_nodes_from_collection_set(eachce)
  
  
subject: Add prior node i.e unit id in course's resources