code: def valid_project(self):
          
          try:
              path = self.projects.get_active_project_path()
          except AttributeError:
              return
  
          if bool(path):
              if not self.projects.is_valid_project(path):
                  if path:
                      QMessageBox.critical(
                          self,
                          _('Error'),
                          _("<b>{}</b> is no longer a valid Spyder project! "
                            "Since it is the current active project, it will "
                            "be closed automatically.").format(path))
                  self.projects.close_project()
docs: Handle an invalid active project.