code: def test_frequency_range_channel_equality():
      """Test the frequency range object: check if two bands are 'equal'."""
      frqr = FrequencyRange(2, 1)
      assert frqr is not None
      assert 1.7 == frqr
      assert 1.2 != frqr
      assert frqr == (2, 1)
  
      assert frqr == (2, 1, "GHz")
  
imports: import unittest
  from datetime import datetime
  import numpy
  import pytest
  from satpy.dataset.dataid import DataID, DataQuery, ModifierTuple, WavelengthRange, minimal_default_keys_config
  from satpy.readers.pmw_channels_definitions import FrequencyDoubleSideBand, FrequencyQuadrupleSideBand, FrequencyRange
  from satpy.tests.utils import make_cid, make_dataid, make_dsq
label_desc: Use image node_id 20 for calling a global function with example usage: test_frequency_range_channel_equality() without return types