def METHOD_NAME(self):
    nc_pseudo_fnames = collections.defaultdict(list)
    nc_pseudo_fnames["Si"] = ref_files("14si.pspnc", "14si.4.hgh", "14-Si.LDA.fhi")
    self.nc_pseudos = collections.defaultdict(list)
    for symbol, fnames in nc_pseudo_fnames.items():
        for fname in fnames:
            root, ext = os.path.splitext(fname)
            pseudo = Pseudo.from_file(fname)
            self.nc_pseudos[symbol].append(pseudo)
            # Save the pseudo as instance attribute whose name
            # is constructed with the rule: symbol_ppformat
            attr_name = symbol + "_" + ext[1:]
            if hasattr(self, attr_name):
                raise RuntimeError(f"self has already the attribute {attr_name}")
            setattr(self, attr_name, pseudo)