def METHOD_NAME(self, widget):
    # If you iterate over widget.selection, you can get the names and the
    # paths of everything selected (if multiple_select is enabled.)
    # filepaths = [node.path for node in widget.selection]
    if isinstance(widget.selection, list):
        files = len(widget.selection)
    else:
        files = 0 if widget.selection is None else 1
    if files == 0:
        self.label.text = "A view of the current directory!"
    elif files == 1:
        self.label.text = f"You selected {files} item"
    else:
        self.label.text = f"You selected {files} items"