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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 async def is_user_authorized(self):
 """ Returns ``True`` if the user is authorized. """

        if self._authorized is None:
            try:
                # Any request that requires authorization will work
                await self(functions.updates.GetStateRequest())
                self._authorized = True
            except errors.RPCError:
                self._authorized = False

        return self._authorized