class_docstr: NWCSAF PPS&MSG NetCDF reader.
code: def _get_varname_in_file(self, info, info_type="file_key"):
      if isinstance(info[info_type], list):
          for key in info[info_type]:
              file_key = self.file_key_prefix + key
              if file_key in self.nc:
                  return file_key
      return self.file_key_prefix + info[info_type]
  
imports: import functools
  import logging
  import os
  from contextlib import suppress
  from datetime import datetime
  import dask.array
  import numpy
  import xarray
  from pyproj import CRS
  from pyresample.geometry import AreaDefinition
  from satpy.readers.file_handlers import BaseFileHandler
  from satpy.readers.utils import unzip_file
  from satpy.utils import get_chunk_size_limit
label_desc: Use image node_id 7 for calling the NcNWCSAF obj's underlying member method code with example usage: obj._get_varname_in_file(info, info_type) and returns: unknown, file_key