def METHOD_NAME(self, mosaic_filename):
    """
    Save the current SteveItems in mosaic file.
    """
    progress_bar = QtWidgets.QProgressDialog("Saving Files...",
                                             "Abort Save",
                                             0,
                                             len(self.items))
    progress_bar.setWindowModality(QtCore.Qt.WindowModal)
    directory = os.path.dirname(mosaic_filename)
    name_no_extension = os.path.splitext(os.path.basename(mosaic_filename))[0]
    with open(mosaic_filename, "w") as fp:
        for i, elt in enumerate(self.itemIterator()):
            progress_bar.setValue(i)
            if progress_bar.wasCanceled():
                break
            line = elt.saveItem(directory, name_no_extension)
            if line is not None:
                fp.write(elt.data_type + "," + line + "\r\n")
    progress_bar.close()