code: def _get_expected_stack_blend(
      scene1: Scene, scene2: Scene
  ) -> xr.DataArray:
      expected = scene2["polar-ct"].copy().compute().astype(np.float64)
      expected[..., NUM_TEST_ROWS, :] = 5 / 3  # (1*2 + 3*1) / (2 + 1)
      expected[..., :, NUM_TEST_COLS] = 5 / 3
      expected[..., -1, :] = np.nan  # (1*0 + 0*1) / (0 + 1)
      # weight of 1 is masked to 0 because invalid overlay value:
      expected[..., -1, NUM_TEST_COLS] = 2 / 2  # (1*2 + 0*1) / (2 + 0)
      return expected
  
imports: from datetime import datetime
  import dask.array
  import numpy
  import pytest
  import xarray
  from pyresample.geometry import AreaDefinition
  from satpy import DataQuery, Scene
  from satpy.multiscene import stack, timeseries
  from satpy.tests.multiscene_tests.test_utils import DEFAULT_SHAPE, _create_test_area, _create_test_dataset, _create_test_int8_dataset
  from satpy.tests.utils import make_dataid
label_desc: Use image node_id 2 for calling a global function with example usage: _get_expected_stack_blend(scene1, scene2) and returns: expected