How to use the nixio.FileMode.Overwrite function in nixio

def write_recording(recording, save_path, overwrite=False):
        assert HAVE_NIXIO, NIXIORecordingExtractor.installation_mesg
        if os.path.exists(save_path) and not overwrite:
            raise FileExistsError("File exists: {}".format(save_path))

        nf = nix.File.open(save_path, nix.FileMode.Overwrite)
        # use the file name to name the top-level block
        fname = os.path.basename(save_path)
        block = nf.create_block(fname, "spikeinterface.recording")
        da = block.create_data_array("traces", "spikeinterface.traces",
                                     data=recording.get_traces())
        da.unit = "uV"
        da.label = "voltage"
        labels = recording.get_channel_ids()
        if not labels:  # channel IDs not specified; just number them
            labels = list(range(recording.get_num_channels()))
        chandim = da.append_set_dimension()
        chandim.labels = labels
        sfreq = recording.get_sampling_frequency()
        timedim = da.append_sampled_dimension(sampling_interval=1./sfreq)
        timedim.unit = "s"

def __init__(self, filename, mode="rw"):
        """
        Initialise IO instance and NIX file.

        :param filename: Full path to the file
        """
        check_nix_version()
        BaseIO.__init__(self, filename)
        self.filename = filename
        if mode == "ro":
            filemode = nix.FileMode.ReadOnly
        elif mode == "rw":
            filemode = nix.FileMode.ReadWrite
        elif mode == "ow":
            filemode = nix.FileMode.Overwrite
        else:
            raise ValueError("Invalid mode specified '{}'. "
                             "Valid modes: 'ro' (ReadOnly)', 'rw' (ReadWrite),"
                             " 'ow' (Overwrite).".format(mode))
        self.nix_file = nix.File.open(self.filename, filemode)

        if self.nix_file.mode == nix.FileMode.ReadOnly:
            self._file_version = '0.5.2'
            if "neo" in self.nix_file.sections:
                self._file_version = self.nix_file.sections["neo"]["version"]
        elif self.nix_file.mode == nix.FileMode.ReadWrite:
            if "neo" in self.nix_file.sections:
                self._file_version = self.nix_file.sections["neo"]["version"]
            else:
                self._file_version = '0.5.2'
                filemd = self.nix_file.create_section("neo", "neo.metadata")