class_docstr: Swap-in HDF5 File Handler.
class_docstr_tok: ["Swap-in","HDF5","File","Handler","."]
code: def _add_geo_ref(file_content, filename):
      if filename[:3] == "SVI":
          geo_prefix = "GIMGO"
      elif filename[:3] == "SVM":
          geo_prefix = "GMODO"
      else:
          geo_prefix = None
      if geo_prefix:
          file_content["/attr/N_GEO_Ref"] = geo_prefix + filename[5:]
  
imports: import os
  import unittest
  from contextlib import contextmanager
  from unittest import mock
  import numpy
  import pytest
  from satpy.readers.viirs_atms_sdr_base import DATASET_KEYS
  from satpy.tests.reader_tests.test_hdf5_utils import FakeHDF5FileHandler
label_desc: Use image node_id 8 for calling the FakeHDF5FileHandler2 obj's underlying member method code with example usage: obj._add_geo_ref(file_content, filename) without return types