class_docstr: Reader for HRPT Minor Frame, 10 bits data expanded to 16 bits.
code: def _get_ch3_mask_or_true(self, key):
      mask = True
      if key["name"] == "3a":
          mask = np.tile(np.logical_not(self._is3b), (2048, 1)).T
      elif key["name"] == "3b":
          mask = np.tile(self._is3b, (2048, 1)).T
      return mask
  
imports: import logging
  from datetime import datetime
  import dask.array
  import numpy
  import xarray
  from geotiepoints import SatelliteInterpolator
  from pyorbital.geoloc import compute_pixels, get_lonlatalt
  from pyorbital.geoloc_instrument_definitions import avhrr
  from pyorbital.orbital import Orbital
  from satpy._compat import cached_property
  from satpy.readers.aapp_l1b import get_avhrr_lac_chunks
  from satpy.readers.file_handlers import BaseFileHandler
label_desc: Use image node_id 10 for calling the HRPTFile obj's underlying member method code with example usage: obj._get_ch3_mask_or_true(key) and returns: mask