class_docstr: SEVIRI native format reader.
  
  **Calibration**
  
  See :mod:`satpy.readers.seviri_base`.
  
  **Padding channel data to full disk**
  
  By providing the `fill_disk` as True in the `reader_kwargs`, the channel is loaded
  as full disk, padded with no-data where necessary. This is especially useful for the
  HRV channel, but can also be used for RSS and ROI data. By default, the original,
  unpadded, data are loaded::
  
      scene = satpy.Scene(filenames,
                          reader='seviri_l1b_native',
                          reader_kwargs={'fill_disk': False})
  
  **Metadata**
  
  See :mod:`satpy.readers.seviri_base`.
docstr: Get general start time for this file.
docstr_tok: ["Get","general","start","time","for","this","file","."]
code: def start_time(self):
      """Get general start time for this file."""
      return self.nominal_start_time
  
imports: import logging
  import warnings
  from datetime import datetime, timedelta
  import dask.array
  import numpy
  import xarray
  from pyresample import geometry
  from satpy._compat import cached_property
  from satpy.readers._geos_area import get_area_definition, get_geos_area_naming
  from satpy.readers.eum_base import get_service_mode, recarray2dict, time_cds_short
  from satpy.readers.file_handlers import BaseFileHandler
  from satpy.readers.seviri_base import CHANNEL_NAMES, HRV_NUM_COLUMNS, HRV_NUM_LINES, REPEAT_CYCLE_DURATION, SATNUM, VISIR_NUM_COLUMNS, VISIR_NUM_LINES, NoValidOrbitParams, OrbitPolynomialFinder, SEVIRICalibrationHandler, add_scanline_acq_time, calculate_area_extent, create_coef_dict, dec10216, get_cds_time, get_satpos, pad_data_horizontally, pad_data_vertically, round_nom_time
  from satpy.readers.seviri_l1b_native_hdr import DEFAULT_15_SECONDARY_PRODUCT_HEADER, GSDTRecords, get_native_header, native_trailer
  from satpy.readers.utils import reduce_mda
  from satpy.utils import get_legacy_chunk_size
label_desc: Use image node_id 7 for calling the NativeMSGFileHandler obj's underlying member method code with example usage: obj.start_time() and returns: self