code: def test_lpca_flow():
      with TemporaryDirectory() as out_dir:
          data_path, fbvals, fbvecs = get_fnames()
  
      lpca_flow = LPCAFlow()
      lpca_flow.run(data_path, fbvals, fbvecs, out_dir=out_dir)
      assert_true(
          os.path.isfile(
              lpca_flow.last_generated_outputs["out_denoised"]
          )
      )
  
file_path: dipy/dipy/workflows/tests/test_denoise.py
imports: import os
  from tempfile import TemporaryDirectory
  import pytest
  import numpy
  import numpy.testing
  from dipy.utils.optpkg import optional_package
  from dipy.data import get_fnames
  from dipy.io.image import save_nifti, load_nifti, load_nifti_data
  from dipy.testing import assert_true, assert_false, assert_greater, assert_less
  from dipy.testing.decorators import set_random_number_generator
  from dipy.workflows.denoise import NLMeansFlow, LPCAFlow, MPPCAFlow, GibbsRingingFlow, Patch2SelfFlow
label_desc: Use image node_id 3 for calling a global function with example usage: test_lpca_flow() without return types