code: def test_sample_stats(self, paths):
      for key, path in paths.items():
          if "missing" in key:
              continue
          inference_data = self.get_inference_data(path)
          assert hasattr(inference_data, "sample_stats")
          assert "step_size" in inference_data.sample_stats.attrs
          assert (
              inference_data.sample_stats.attrs["step_size"]
              == "stepsize"
          )
  
imports: import os
  import numpy
  import pytest
  from ...None import from_cmdstan
  from ..helpers import check_multiple_attrs
label_desc: Use image node_id 5 for calling the TestDataCmdStan obj's underlying member method code with example usage: obj.test_sample_stats(paths) without return types