class_docstr: Class implementing the MTG FCI L1c Filehandler.
  
  This class implements the Meteosat Third Generation (MTG) Flexible
  Combined Imager (FCI) Level-1c NetCDF reader.
  It is designed to be used through the :class:`~satpy.Scene`
  class using the :mod:`~satpy.Scene.load` method with the reader
  ``"fci_l1c_nc"``.
docstr: Calibrate counts to radiances.
docstr_tok: ["Calibrate","counts","to","radiances","."]
code: def calibrate_counts_to_rad(self, data, key):
      """Calibrate counts to radiances."""
      if key["name"] == "ir_38":
          data = xr.where(
              ((2**12 - 1 < data) & (data <= 2**13 - 1)),
              (
                  data * data.attrs.get("warm_scale_factor", 1)
                  + data.attrs.get("warm_add_offset", 0)
              ),
              (
                  data * data.attrs.get("scale_factor", 1)
                  + data.attrs.get("add_offset", 0)
              ),
          )
      else:
          data = data * data.attrs.get(
              "scale_factor", 1
          ) + data.attrs.get("add_offset", 0)
  
      measured = self.get_channel_measured_group_path(key["name"])
      data.attrs.update(
          {
              "radiance_unit_conversion_coefficient": self.get_and_cache_npxr(
                  measured + "/radiance_unit_conversion_coefficient"
              )
          }
      )
      return data
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import logging
  from datetime import timedelta
  from functools import cached_property
  import dask.array
  import numpy
  import xarray
  from netCDF4 import default_fillvals
  from pyresample import geometry
  from satpy.readers._geos_area import get_geos_area_naming
  from satpy.readers.eum_base import get_service_mode
  from .netcdf_utils import NetCDF4FsspecFileHandler
label_desc: Use image node_id 23 for calling the FCIL1cNCFileHandler obj's underlying member method code with example usage: obj.calibrate_counts_to_rad(data, key) and returns: data