code: def fake_open_dataset(filename, **kwargs):
      """Create a Dataset similar to reading an actual file with xarray.open_dataset."""
      if filename in [MBT_FILENAME, PRECIP_FILENAME, OCEAN_FILENAME]:
          return _create_two_res_gaasp_dataset(filename)
      if filename in [SEAICE_NH_FILENAME, SEAICE_SH_FILENAME]:
          return _create_gridded_gaasp_dataset(filename)
      return _create_one_res_gaasp_dataset(filename)
  
file_path: satpy/satpy/tests/reader_tests/test_amsr2_l2_gaasp.py
imports: import os
  from datetime import datetime
  from unittest import mock
  import dask.array
  import numpy
  import pytest
  import xarray
label_desc: Use image node_id 5 for calling a global function with example usage: fake_open_dataset(filename) and returns: _create_one_res_gaasp_dataset, _create_two_res_gaasp_dataset, _create_gridded_gaasp_dataset