docs: def unhandled_keys(self, size, key):
          """
          Override this method to intercept keystrokes in subclasses.
          Default behavior: Toggle flagged on space, ignore other keys.
          """
          if key == " ":
              if not self.flagged:
                  self.display.new_files.append(self.get_node().get_value())
              else:
                  self.display.new_files.remove(self.get_node().get_value())
              self.flagged = not self.flagged
              self.update_w()
              self.display.update_status()
          else:
              return key