class_docstr: Test VISSR file handler.
class_docstr_tok: ["Test","VISSR","file","handler","."]
docstr: Get VIS calibration block.
docstr_tok: ["Get","VIS","calibration","block","."]
code: def vis_calibration(self):
      """Get VIS calibration block."""
      vis_cal = np.zeros(1, dtype=fmt.VIS_CALIBRATION)
      table = vis_cal["vis1_calibration_table"][
          "brightness_albedo_conversion_table"
      ]
      table[0, 0:4] = np.array([0, 0.25, 0.5, 1])
      return vis_cal
  
imports: import datetime
  import gzip
  import fsspec
  import numpy
  import pytest
  import xarray
  from pyresample.geometry import AreaDefinition
  import satpy.tests.reader_tests.gms.test_gms5_vissr_data
  from satpy.readers import FSFile
  from satpy.tests.reader_tests.utils import get_jit_methods, skip_numba_unstable_if_missing
  from satpy.tests.utils import make_dataid
label_desc: Use image node_id 19 for calling the TestFileHandler obj's underlying member method code with example usage: obj.vis_calibration() and returns: vis_cal