How to use the h5py.is_hdf5 function in h5py

def getFileHandle(self,inputfile):
        try:
            self._HDF5 = False
            if HDF5SUPPORT:
                if h5py.is_hdf5(inputfile):
                    self._HDF5 = True
                    try:
                        return HDF5Stack1D.HDF5Stack1D(self._filelist,
                                                      self.selection)
                    except:
                        raise
            ffile = self.__tryEdf(inputfile)
            if ffile is None:
                ffile = self.__tryLucia(inputfile)
            if ffile is None:
                if inputfile[-3:] == "DAT":
                    ffile = self.__tryAifira(inputfile)
            if (ffile is None):
                del ffile
                ffile   = SpecFileLayer.SpecFileLayer()
                ffile.SetSource(inputfile)

print(">filename:", filename)
    print(">username:", username)
    print(">password:", passwd)
    print(">email:", email)
    
    
    if args.replace:
        print("replace is on")
        
        
    # verify file exists and is writable
    if not op.isfile(filename):
        print("password file:", filename, " does not exist")
        return -1
        
    if not h5py.is_hdf5(filename):
        print("invalid password file")
        return -1
        
    mode = 'r'
    if args.replace or args.add:
        mode = 'r+'
    
        if not os.access(filename, os.W_OK):
            print("password file is not writable")
            return -1
    
    f = h5py.File(filename, mode)
    if 'user_type' not in f:
        print("invalid password file")
        return -1

return -1
    
    if args.passwd:
        passwd = args.passwd
        if len(passwd) < 4:
            print("password must be at least 4 characters long")
            return -1
    else:
        passwd = generate_temp_password()
        
    # verify file exists and is writable
    if not op.isfile(filename):
        print("password file:", filename, " does not exist")
        return -1
        
    if not h5py.is_hdf5(filename):
        print("invalid password file")
        return -1
        
    if not os.access(filename, os.W_OK):
        print("password file is not writable")
        return -1
    
    f = h5py.File(filename, 'r+')
    if 'user_type' not in f:
        print("invalid password file")
        return -1
        
    user_type = f['user_type']
       
    
    now = int(time.time())

def read(self, filename, load_lonlat=True):
        """Read product in hdf format from *filename*
        """
        LOG.debug("Filename: %s" % filename)

        is_temp = False
        if not h5py.is_hdf5(filename):
            # Try see if it is bzipped:
            import bz2
            bz2file = bz2.BZ2File(filename)
            import tempfile
            tmpfilename = tempfile.mktemp()
            try:
                ofpt = open(tmpfilename, 'wb')
                ofpt.write(bz2file.read())
                ofpt.close()
                is_temp = True
            except IOError:
                import traceback
                traceback.print_exc()
                raise IOError("Failed to read the file %s" % filename)

            filename = tmpfilename

def open_file(file_name):
    if h5.is_hdf5(file_name):
        f = h5.File(file_name, "r")
        return(f)
    else:
        help()

def dump_mcscf(mc, chkfile=None, key='mcscf',
               e_tot=None, mo_coeff=None, ncore=None, ncas=None,
               mo_occ=None, mo_energy=None, e_cas=None, ci_vector=None,
               casdm1=None, overwrite_mol=True):
    '''Save CASCI/CASSCF calculation results or intermediates in chkfile.
    '''
    if chkfile is None: chkfile = mc.chkfile
    if ncore is None: ncore = mc.ncore
    if ncas is None: ncas = mc.ncas
    if e_tot is None: e_tot = mc.e_tot
    if e_cas is None: e_cas = mc.e_cas
    if mo_coeff is None: mo_coeff = mc.mo_coeff
    #if ci_vector is None: ci_vector = mc.ci

    if h5py.is_hdf5(chkfile):
        fh5 = h5py.File(chkfile)
        if key in fh5:
            del(fh5[key])
    else:
        fh5 = h5py.File(chkfile, 'w')

    if 'mol' not in fh5:
        fh5['mol'] = mc.mol.dumps()
    elif overwrite_mol:
        del(fh5['mol'])
        fh5['mol'] = mc.mol.dumps()

    fh5[key+'/mo_coeff'] = mo_coeff

    def store(subkey, val):
        if val is not None:

detected_input_format = common.TF_HUB_MODEL
  elif os.path.isdir(input_path):
    if (any(fname.lower().endswith('saved_model.pb')
            for fname in os.listdir(input_path))):
      detected_input_format = detect_saved_model(input_path)
    else:
      for fname in os.listdir(input_path):
        fname = fname.lower()
        if fname.endswith('model.json'):
          filename = os.path.join(input_path, fname)
          if get_tfjs_model_type(filename) == common.TFJS_LAYERS_MODEL_FORMAT:
            input_path = os.path.join(input_path, fname)
            detected_input_format = common.TFJS_LAYERS_MODEL
            break
  elif os.path.isfile(input_path):
    if h5py.is_hdf5(input_path):
      detected_input_format = common.KERAS_MODEL
    elif input_path.endswith('saved_model.pb'):
      input_path = os.path.dirname(input_path)
      detected_input_format = detect_saved_model(input_path)
    elif (input_path.endswith('model.json') and
          get_tfjs_model_type(input_path) == common.TFJS_LAYERS_MODEL_FORMAT):
      detected_input_format = common.TFJS_LAYERS_MODEL

  return detected_input_format, input_path