class_docstr: Test case for CF reader.
class_docstr_tok: ["Test","case","for","CF","reader","."]
docstr: Check channels starting with digit is prefixed and read back correctly.
docstr_tok: ["Check","channels","starting","with","digit","is","prefixed","and","read","back","correctly","."]
code: def test_read_prefixed_channels(self, cf_scene, nc_filename):
      """Check channels starting with digit is prefixed and read back correctly."""
      cf_scene.save_datasets(
          writer="cf",
          filename=nc_filename,
          engine="netcdf4",
          flatten_attrs=True,
          pretty=True,
      )
      scn_ = Scene(reader="satpy_cf_nc", filenames=[nc_filename])
      scn_.load(["1"])
      np.testing.assert_array_equal(scn_["1"].data, cf_scene["1"].data)
      np.testing.assert_array_equal(
          scn_["1"].coords["lon"], cf_scene["lon"].data
      )  # lon loaded as coord
  
      scn_ = Scene(
          reader="satpy_cf_nc",
          filenames=[nc_filename],
          reader_kwargs={},
      )
      scn_.load(["1"])
      np.testing.assert_array_equal(scn_["1"].data, cf_scene["1"].data)
      np.testing.assert_array_equal(
          scn_["1"].coords["lon"], cf_scene["lon"].data
      )  # lon loaded as coord
  
      # Check that variables starting with a digit is written to filename variable prefixed
      with xr.open_dataset(nc_filename) as ds_disk:
          np.testing.assert_array_equal(
              ds_disk["CHANNEL_1"].data, cf_scene["1"].data
          )
  
imports: import warnings
  from datetime import datetime
  import numpy
  import pytest
  import xarray
  from pyresample import AreaDefinition, SwathDefinition
  from satpy import Scene
  from satpy.dataset.dataid import WavelengthRange
  from satpy.readers.satpy_cf_nc import SatpyCFFileHandler
label_desc: Use image node_id 4 for calling the TestCFReader obj's underlying member method code with example usage: obj.test_read_prefixed_channels(cf_scene, nc_filename) without return types