class_docstr: Test case for CF reader.
class_docstr_tok: ["Test","case","for","CF","reader","."]
docstr: Check channels starting with digit is not prefixed by user.
docstr_tok: ["Check","channels","starting","with","digit","is","not","prefixed","by","user","."]
code: def test_read_prefixed_channels_by_user_no_prefix(
      self, cf_scene, nc_filename
  ):
      """Check channels starting with digit is not prefixed by user."""
      with warnings.catch_warnings():
          warnings.filterwarnings(
              "ignore",
              category=UserWarning,
              message=".*starts with a digit.*",
          )
          cf_scene.save_datasets(
              writer="cf",
              filename=nc_filename,
              engine="netcdf4",
              flatten_attrs=True,
              pretty=True,
              numeric_name_prefix="",
          )
      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
      )
  
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 9 for calling the TestCFReader obj's underlying member method code with example usage: obj.test_read_prefixed_channels_by_user_no_prefix(cf_scene, nc_filename) without return types