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Zed ddZe edddZdS ) )DictN)BackendDatagramSocketSocket StreamSocket _backendsFc @ s e Zd ZdS )AsyncLibraryNotFoundErrorN)__name__
__module__ __qualname__ r r 4/usr/lib/python3.9/site-packages/dns/asyncbackend.pyr s r )namereturnc C sd t | }|r|S | dkr.ddl}|j }n*| dkrJddl}|j }ntd| |t | < |S )zGet the specified asynchronous backend.
*name*, a ``str``, the name of the backend. Currently the "trio"
and "asyncio" backends are available.
Raises NotImplementedError if an unknown backend name is specified.
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tddl} z | W W S | jy: tdY n0 W nF ty ddl}z| W Y dS ty~ tdY n0 Y n0 dS )zAttempt to determine the in-use asynchronous I/O library by using
the ``sniffio`` module if it is available.
Returns the name of the library, or raises AsyncLibraryNotFoundError
if the library cannot be determined.
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sniff7 s r c C s t rt S tt S )z6Get the default backend, initializing it if necessary.)_default_backendset_default_backendr r r r r
get_default_backendR s r c C s t | atS )a, Set the default backend.
It's not normally necessary to call this method, as
``get_default_backend()`` will initialize the backend
appropriately in many cases. If ``sniffio`` is not installed, or
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explicitly.
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