class_docstr: Test case for CF reader.
class_docstr_tok: ["Test","case","for","CF","reader","."]
docstr: Check channels starting with digit is prefixed by user when saving and read back correctly without prefix.
docstr_tok: ["Check","channels","starting","with","digit","is","prefixed","by","user","when","saving","and","read","back","correctly","without","prefix","."]
code: def test_read_prefixed_channels_by_user2(self, cf_scene, nc_filename):
      """Check channels starting with digit is prefixed by user when saving and read back correctly without prefix."""
      cf_scene.save_datasets(
          writer="cf",
          filename=nc_filename,
          engine="netcdf4",
          flatten_attrs=True,
          pretty=True,
          include_orig_name=False,
          numeric_name_prefix="USER",
      )
      scn_ = Scene(reader="satpy_cf_nc", filenames=[nc_filename])
      scn_.load(["USER1"])
      np.testing.assert_array_equal(
          scn_["USER1"].data, cf_scene["1"].data
      )
      np.testing.assert_array_equal(
          scn_["USER1"].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 7 for calling the TestCFReader obj's underlying member method code with example usage: obj.test_read_prefixed_channels_by_user2(cf_scene, nc_filename) without return types