class_docstr: Provides scoped management of :class:`.AsyncSession` objects.
  
  See the section :ref:`asyncio_scoped_session` for usage details.
  
  .. versionadded:: 1.4.19
class_docstr_tok: ["Provides","scoped","management","of",":","class",":","`",".AsyncSession","`","objects",".","See","the","section",":","ref",":","`","asyncio_scoped_session","`","for","usage","details",".","..","versionadded",":",":","1.4.19"]
docstr: Return an :class:`_asyncio.AsyncSessionTransaction` object
  which will begin a "nested" transaction, e.g. SAVEPOINT.
  
  .. container:: class_bases
  
      Proxied for the :class:`_asyncio.AsyncSession` class on
      behalf of the :class:`_asyncio.scoping.async_scoped_session` class.
  
  Behavior is the same as that of :meth:`_asyncio.AsyncSession.begin`.
  
  For a general description of ORM begin nested, see
  :meth:`_orm.Session.begin_nested`.
  
  .. seealso::
  
      :ref:`aiosqlite_serializable` - special workarounds required
      with the SQLite asyncio driver in order for SAVEPOINT to work
      correctly.
code: def begin_nested(self) -> AsyncSessionTransaction:
      r"""Return an :class:`_asyncio.AsyncSessionTransaction` object
      which will begin a "nested" transaction, e.g. SAVEPOINT.
  
      .. container:: class_bases
  
          Proxied for the :class:`_asyncio.AsyncSession` class on
          behalf of the :class:`_asyncio.scoping.async_scoped_session` class.
  
      Behavior is the same as that of :meth:`_asyncio.AsyncSession.begin`.
  
      For a general description of ORM begin nested, see
      :meth:`_orm.Session.begin_nested`.
  
      .. seealso::
  
          :ref:`aiosqlite_serializable` - special workarounds required
          with the SQLite asyncio driver in order for SAVEPOINT to work
          correctly.
  
  
      """  # noqa: E501
  
      return self._proxied.begin_nested()
  
imports: from __future__ import annotations
  from typing import Any
  from typing import Callable
  from typing import Generic
  from typing import Iterable
  from typing import Iterator
  from typing import Optional
  from typing import overload
  from typing import Sequence
  from typing import Tuple
  from typing import Type
  from typing import TYPE_CHECKING
  from typing import TypeVar
  from typing import Union
  from .session import _AS
  from .session import async_sessionmaker
  from .session import AsyncSession
  from ...None import exc
  from ...None import util
  from ...orm.session import Session
  from ...util import create_proxy_methods
  from ...util import ScopedRegistry
  from ...util import warn
  from ...util import warn_deprecated
label_desc: Use image node_id 10 for calling the async_scoped_session obj's underlying member method code with example usage: obj.begin_nested() and returns: self