def METHOD_NAME(self):
    hvals = self._get_hvals()
    self.dimensionality = 3
    self.refine_by = 2
    self.parameters["HydroMethod"] = "sph"
    # Set standard values
    # We may have an overridden bounding box.
    if self.domain_left_edge is None and hvals["BoxSize"] != 0:
        self.domain_left_edge = np.zeros(3, "float64")
        self.domain_right_edge = np.ones(3, "float64") * hvals["BoxSize"]
    self.domain_dimensions = np.ones(3, "int32")
    self._periodicity = (True, True, True)
    self.cosmological_simulation = 1
    self.current_redshift = hvals.get("Redshift", 0.0)
    if "Redshift" not in hvals:
        mylog.info("Redshift is not set in Header. Assuming z=0.")
    if "ComovingIntegrationOn" in hvals:
        # In 1d8479, Nov 2020, public GIZMO updated the names of the Omegas
        # to include an _, added baryons and radiation and added the
        # ComovingIntegrationOn field. ComovingIntegrationOn is always set,
        # but the Omega's are only included if ComovingIntegrationOn is true
        mylog.debug("Reading cosmological parameters using post-1d8479 format")
        self.cosmological_simulation = hvals["ComovingIntegrationOn"]
        if self.cosmological_simulation:
            self.omega_lambda = hvals["Omega_Lambda"]
            self.omega_matter = hvals["Omega_Matter"]
            self.omega_baryon = hvals["Omega_Baryon"]
            self.omega_radiation = hvals["Omega_Radiation"]
        self.hubble_constant = hvals["HubbleParam"]
    elif "OmegaLambda" in hvals:
        # Should still support GIZMO versions prior to 1d8479 too
        mylog.info(
            "ComovingIntegrationOn does not exist, falling back to OmegaLambda",
        )
        self.omega_lambda = hvals["OmegaLambda"]
        self.omega_matter = hvals["Omega0"]
        self.hubble_constant = hvals["HubbleParam"]
        self.cosmological_simulation = self.omega_lambda != 0.0
    else:
        # If these are not set it is definitely not a cosmological dataset.
        mylog.debug("No cosmological information found, assuming defaults")
        self.omega_lambda = 0.0
        self.omega_matter = 0.0  # Just in case somebody asks for it.
        self.cosmological_simulation = 0
        # Hubble is set below for Omega Lambda = 0.
    if not self.cosmological_simulation:
        mylog.info(
            "ComovingIntegrationOn != 1 or (not found "
            "and OmegaLambda is 0.0), so we are turning off Cosmology.",
        )
        self.hubble_constant = 1.0  # So that scaling comes out correct
        self.current_redshift = 0.0
        # This may not be correct.
        self.current_time = hvals["Time"]
    else:
        # Now we calculate our time based on the cosmology, because in
        # ComovingIntegration hvals["Time"] will in fact be the expansion
        # factor, not the actual integration time, so we re-calculate
        # global time from our Cosmology.
        cosmo = Cosmology(
            hubble_constant=self.hubble_constant,
            omega_matter=self.omega_matter,
            omega_lambda=self.omega_lambda,
        )
        self.current_time = cosmo.lookback_time(self.current_redshift, 1e6)
        mylog.info(
            "Calculating time from %0.3e to be %0.3e seconds",
            hvals["Time"],
            self.current_time,
        )
    self.parameters = hvals
    prefix = os.path.join(self.directory, self.basename.split(".", 1)[0])
    if hvals["NumFiles"] > 1:
        self.filename_template = f"{prefix}.%(num)s{self._suffix}"
    else:
        self.filename_template = self.parameter_filename
    self.file_count = hvals["NumFiles"]