code: def test_process_xarray_dataset_with_by_as_derived_datetime(self):
      import pandas as pd
  
      data = self.ds.mean(dim=["lat", "lon"])
      kwargs = self.default_kwargs
      kwargs.update(gridded=False, y="air", by=["time.hour"])
  
      data, x, y, by, groupby = process_xarray(data=data, **kwargs)
      assert isinstance(data, pd.DataFrame)
      assert x == "time"
      assert y == "air"
      assert by == ["time.hour"]
      assert not groupby
  
imports: import numpy
  import pandas
  import pytest
  from unittest import TestCase, SkipTest
  from hvplot.util import check_crs, is_list_like, process_crs, process_xarray, _convert_col_names_to_str, instantiate_crs_str
label_desc: Use image node_id 11 for calling the TestProcessXarray obj's underlying member method code with example usage: obj.test_process_xarray_dataset_with_by_as_derived_datetime() without return types