code: def from_environ(cls, environ=os.environ):
      
      base_path, unused = (environ['PATH_INFO'].rsplit('/', 1) + [''])[:2]
      return cls(
          environ['HTTP_X_APPENGINE_TASKNAME'],
          environ['HTTP_X_APPENGINE_QUEUENAME'],
          base_path)
docs: Constructs a _PipelineContext from the task queue environment.