class_docstr: Swap-in HDF5 File Handler.
class_docstr_tok: ["Swap-in","HDF5","File","Handler","."]
code: def _create_coeff_array(self, nb_channels):
      data = xr.DataArray(
          da.from_array(
              (
                  np.arange(nb_channels * 2).reshape((nb_channels, 2))
                  + 1.0
              )
              / np.array([1e4, 1e2]),
              [nb_channels, 2],
          ),
          attrs={
              "Slope": 1.0,
              "Intercept": 0.0,
              "FillValue": 0,
              "units": "NUL",
              "band_names": "NUL",
              "long_name": b"Calibration coefficient (SCALE and OFFSET)",
              "valid_range": [-500, 500],
          },
          dims=("_num_channel", "_coefs"),
      )
      return data
  
imports: import os
  from unittest import mock
  import dask.array
  import numpy
  import pytest
  import xarray
  from satpy.tests.reader_tests.test_hdf5_utils import FakeHDF5FileHandler
label_desc: Use image node_id 2 for calling the FakeHDF5FileHandler2 obj's underlying member method code with example usage: obj._create_coeff_array(nb_channels) and returns: data