async def get(self,request_configuration: Optional[RequestConfiguration[GetAllRetainedMessagesRequestBuilderGetQueryParameters]] = None) -> Optional[GetAllRetainedMessagesGetResponse]:
        """
        Get all retained messages across all channels in a team. To learn more about how to use the Microsoft Teams export APIs to export content, see Export content with the Microsoft Teams export APIs.
        param request_configuration: Configuration for the request such as headers, query parameters, and middleware options.
        Returns: Optional[GetAllRetainedMessagesGetResponse]
        Find more info here: https://learn.microsoft.com/graph/api/channel-getallretainedmessages?view=graph-rest-1.0
        """
        request_info = self.to_get_request_information(
            request_configuration
        )
        from ......models.o_data_errors.o_data_error import ODataError

        error_mapping: dict[str, type[ParsableFactory]] = {
            "XXX": ODataError,
        }
        if not self.request_adapter:
            raise Exception("Http core is null") 
        from .get_all_retained_messages_get_response import GetAllRetainedMessagesGetResponse

        return await self.request_adapter.send_async(request_info, GetAllRetainedMessagesGetResponse, error_mapping)

        Get all retained messages across all channels in a team. To learn more about how to use the Microsoft Teams export APIs to export content, see Export content with the Microsoft Teams export APIs.
        param request_configuration: Configuration for the request such as headers, query parameters, and middleware options.
        Returns: Optional[GetAllRetainedMessagesGetResponse]
        Find more info here: https://learn.microsoft.com/graph/api/channel-getallretainedmessages?view=graph-rest-1.0
        
msgraph/generated/groups/item/team/channels/get_all_retained_messages/get_all_retained_messages_request_builder.py