def import_events(self, source='wonambi'):
        """action: import events from text file (Wonambi or RemLogic)."""
        if self.annot is None:  # remove if buttons are disabled
            self.parent.statusBar().showMessage('No score file loaded')
            return

        if 'wonambi' == source:
            format_str = 'CSV File (*.csv)'
            rec_start = None
        
        elif 'remlogic' == source:
            format_str = 'Text file (*.txt)'
            rec_start = self.parent.info.dataset.header['start_time']
            
        
        fn, _ = QFileDialog.getOpenFileName(self, 'Import events',
                                            None, format_str)
        
        if fn == '':
            return
        
        fn = Path(fn).resolve()

        self.annot.import_events(fn, source=source, rec_start=rec_start,
                                 parent=self.parent)
        self.display_notes()
action: import events from text file (Wonambi or RemLogic).