class_docstr: Special exception to return a value from a `coroutine`.
  
  If this exception is raised, its value argument is used as the
  result of the coroutine::
  
      @gen.coroutine
      def fetch_json(url):
          response = yield AsyncHTTPClient().fetch(url)
          raise gen.Return(json_decode(response.body))
  
  In Python 3.3, this exception is no longer necessary: the ``return``
  statement can be used directly to return a value (previously
  ``yield`` and ``return`` with a value could not be combined in the
  same function).
  
  By analogy with the return statement, the value argument is optional,
  but it is never necessary to ``raise gen.Return()``.  The ``return``
  statement can be used with no arguments instead.
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code: def __init__(self, value: Any = None) -> None:
      super().__init__()
      self.value = value
      # Cython recognizes subclasses of StopIteration with a .args tuple.
      self.args = (value,)
  
imports: import asyncio
  import builtins
  import collections
  from collections.abc import Generator
  import concurrent.futures
  import datetime
  import functools
  from functools import singledispatch
  from inspect import isawaitable
  import sys
  import types
  from tornado.concurrent import Future, is_future, chain_future, future_set_exc_info, future_add_done_callback, future_set_result_unless_cancelled
  from tornado.ioloop import IOLoop
  from tornado.log import app_log
  from tornado.util import TimeoutError
  import typing
  from typing import Union, Any, Callable, List, Type, Tuple, Awaitable, Dict, overload
label_desc: Use image node_id 1 to create a new Return object from inherited base classes: Exception with example: obj = Return(value)