def METHOD_NAME(self):
    self._handle = h5py.File(self._image_file, "r")
    self.HAS_SPECTRUM_BEAM = False
    if hasattr(Beam, "set_spectrum"):
        self.HAS_SPECTRUM_BEAM = True
    self._image_dset = self._handle["images"]
    self._geometry_define()
    self._has_spectra = False
    self._has_central_wavelengths = False
    self._energies = None
    self._weights = None
    self._central_wavelengths = None
    self._check_per_shot_spectra()
    self._ENERGY_CONV = 12398.419739640716