PyQt slot called when the user hits the "Browse" button.
        Display a directory selection dialog and store the returned path.

def on_browse_button_pressed(self):
        """
        PyQt slot called when the user hits the "Browse" button.
        Display a directory selection dialog and store the returned path.
        """
        path = QFileDialog.getExistingDirectory(self.parentWidget(), "Choose a directory containing Python modules")

        if path:  # Non-empty means the user chose a path and clicked on OK
            self.path = path
            self.clear_button.setEnabled(True)
            self.folder_label.setText(path)
            logger.debug("User selects a custom module search path: {}".format(self.path))