code: def nwcsaf_geo_ct_filename(tmp_path_factory):
      """Create a CT file and return the filename."""
      return create_nwcsaf_geo_ct_file(tmp_path_factory.mktemp("data"))
  
imports: import h5netcdf
  import numpy
  import pytest
  import xarray
  from satpy.readers.nwcsaf_nc import NcNWCSAF, read_nwcsaf_time
label_desc: Use image node_id 1 for calling a global function with example usage: nwcsaf_geo_ct_filename(tmp_path_factory) and returns: create_nwcsaf_geo_ct_file