class_docstr: Test GRIB Reader.
class_docstr_tok: ["Test","GRIB","Reader","."]
code: def _get_fake_pygrib(proj_params, lon_corners, lat_corners):
      latlons = None
      if lon_corners is not None:
          lats = np.array(
              [
                  [lat_corners[0], 0, 0, 0, lat_corners[1]],
                  [0, 0, 0, 0, 0],
                  [0, 0, 0, 0, 0],
                  [0, 0, 0, 0, 0],
                  [lat_corners[2], 0, 0, 0, lat_corners[3]],
              ]
          )
          lons = np.array(
              [
                  [lon_corners[0], 0, 0, 0, lon_corners[1]],
                  [0, 0, 0, 0, 0],
                  [0, 0, 0, 0, 0],
                  [0, 0, 0, 0, 0],
                  [lon_corners[2], 0, 0, 0, lon_corners[3]],
              ]
          )
          latlons = (lats, lons)
  
      fake_pygrib = FakeGRIB(proj_params=proj_params, latlons=latlons)
      return fake_pygrib
  
imports: import os
  import sys
  from unittest import mock
  import numpy
  import pytest
  import xarray
  from satpy.dataset import DataQuery
label_desc: Use image node_id 4 for calling the TestGRIBReader obj's underlying member method code with example usage: obj._get_fake_pygrib(proj_params, lon_corners, lat_corners) and returns: fake_pygrib