class_docstr: JMA HRIT format reader.
  
  By default, the reader uses the start time parsed from the filename. To use exact time, computed
  from the metadata, the user can define a keyword argument::
  
      scene = Scene(filenames=filenames,
                    reader='ahi_hrit',
                    reader_kwargs={'use_acquisition_time_as_start_time': True})
  
  As this time is different for every channel, time-dependent calculations like SZA correction
  can be pretty slow when multiple channels are used.
  
  The exact scanline times are always available as coordinates of an individual channels::
  
      scene.load(["B03"])
      print(scene["B03].coords["acq_time"].data)
  
  would print something similar to::
  
      array(['2021-12-08T06:00:20.131200000', '2021-12-08T06:00:20.191948000',
             '2021-12-08T06:00:20.252695000', ...,
             '2021-12-08T06:09:39.449390000', '2021-12-08T06:09:39.510295000',
             '2021-12-08T06:09:39.571200000'], dtype='datetime64[ns]')
  
  The first value represents the exact start time, and the last one the exact end time of the data
  acquisition.
docstr: Get the dataset designated by *key*.
docstr_tok: ["Get","the","dataset","designated","by","*","key","*","."]
code: def get_dataset(self, key, info):
      """Get the dataset designated by *key*."""
      res = super(HRITJMAFileHandler, self).get_dataset(key, info)
  
      # Filenames of segmented data is identical for MTSAT-1R, MTSAT-2
      # and Himawari-8/9. Make sure we have the correct reader for the data
      # at hand.
      self._check_sensor_platform_consistency(info["sensor"])
  
      # Calibrate and mask space pixels
      res = self._mask_space(self.calibrate(res, key["calibration"]))
  
      # Add scanline acquisition time
      res.coords["acq_time"] = ("y", self.acq_time)
      res.coords["acq_time"].attrs[
          "long_name"
      ] = "Scanline acquisition time"
  
      # Update attributes
      res.attrs.update(info)
      res.attrs["platform_name"] = self.platform
      res.attrs["orbital_parameters"] = {
          "projection_longitude": float(
              self.mda["projection_parameters"]["SSP_longitude"]
          ),
          "projection_latitude": 0.0,
          "projection_altitude": float(
              self.mda["projection_parameters"]["h"]
          ),
      }
  
      return res
  
imports: import logging
  from datetime import datetime
  import numpy
  import xarray
  from satpy.readers._geos_area import get_area_definition, get_area_extent
  from satpy.readers.hrit_base import HRITFileHandler, ancillary_text, annotation_header, base_hdr_map, image_data_function
  from satpy.readers.utils import get_geostationary_mask
label_desc: Use image node_id 7 for calling the HRITJMAFileHandler obj's underlying member method code with example usage: obj.get_dataset(key, info) and returns: res