code: def test_nonzero_scalar_cost(self, cost_manager):
      message = (
          "treatment_cost must be a list with the same number "
          "of elements as treatment_features where each "
          "element is either a constant cost of treatment "
          "or an array specifying the cost of treatment per "
          "sample. Found treatment_cost "
          "of type <class 'int'>, expected list."
      )
      with pytest.raises(UserConfigValidationException, match=message):
          cost_manager.add(
              ["AveRooms", "Population", "AveOccup"], treatment_cost=5
          )
  
imports: import os
  from unittest.mock import ANY, patch
  import numpy
  import pytest
  from raiutils.exceptions import UserConfigValidationException
  from raiutils.models import ModelTask
  from responsibleai import RAIInsights
  from responsibleai._interfaces import CausalData
  from responsibleai._internal.constants import FileFormats
  from responsibleai._tools.shared.state_directory_management import DirectoryManager
  from responsibleai.managers.causal_manager import CausalManager
label_desc: Use image node_id 2 for calling the TestCausalManagerTreatmentCosts obj's underlying member method code with example usage: obj.test_nonzero_scalar_cost(cost_manager) without return types