class_docstr: Unit tests for the slope of Meirink calibration.
docstr: Test the value of the slope of the Meirink calibration on 2000-01-01.
docstr_tok: ["Test","the","value","of","the","slope","of","the","Meirink","calibration","on","2000-01-01","."]
code: def test_get_meirink_slope_epoch(self, platform_id, channel_name):
      """Test the value of the slope of the Meirink calibration on 2000-01-01."""
      coefs = {"coefs": {}}
      coefs["coefs"]["NOMINAL"] = {"gain": -1, "offset": -1}
      coefs["coefs"]["EXTERNAL"] = {}
      calibration_handler = SEVIRICalibrationHandler(
          platform_id,
          channel_name,
          coefs,
          "MEIRINK-2023",
          MEIRINK_EPOCH,
      )
      assert (
          calibration_handler.get_gain_offset()[0]
          == MEIRINK_COEFS["2023"][platform_id][channel_name][0]
          / 1000.0
      )
  
imports: import unittest
  from datetime import datetime, timedelta
  import dask.array
  import numpy
  import pytest
  import xarray
  from satpy.readers.seviri_base import MEIRINK_COEFS, MEIRINK_EPOCH, NoValidOrbitParams, OrbitPolynomial, OrbitPolynomialFinder, SEVIRICalibrationHandler, chebyshev, dec10216, get_cds_time, get_padding_area, get_satpos, pad_data_horizontally, pad_data_vertically, round_nom_time
  from satpy.utils import get_legacy_chunk_size
label_desc: Use image node_id 1 for calling the TestMeirinkSlope obj's underlying member method code with example usage: obj.test_get_meirink_slope_epoch(platform_id, channel_name) without return types