Helper to show the status of the last call to the export method.

def last_export_status(self):
        "Helper to show the status of the last call to the export method."
        if self.export_success is True:
            print("The last call to holoviews.archive.export was successful.")
            return
        elif self.export_success is None:
            print("Status of the last call to holoviews.archive.export is unknown."
                  "\n(Re-execute this method once kernel status is idle.)")
            return
        print("The last call to holoviews.archive.export was unsuccessful.")
        if self.traceback is None:
            print("\n<No traceback captured>")
        else:
            print("\n"+self.traceback)