def by_extension_id(self,extension_id: str) -> ExtensionItemRequestBuilder:
        """
        Provides operations to manage the extensions property of the microsoft.graph.administrativeUnit entity.
        param extension_id: The unique identifier of extension
        Returns: ExtensionItemRequestBuilder
        """
        if extension_id is None:
            raise TypeError("extension_id cannot be null.")
        from .item.extension_item_request_builder import ExtensionItemRequestBuilder

        url_tpl_params = get_path_parameters(self.path_parameters)
        url_tpl_params["extension%2Did"] = extension_id
        return ExtensionItemRequestBuilder(self.request_adapter, url_tpl_params)

        Provides operations to manage the extensions property of the microsoft.graph.administrativeUnit entity.
        param extension_id: The unique identifier of extension
        Returns: ExtensionItemRequestBuilder
        
msgraph/generated/directory/administrative_units/item/extensions/extensions_request_builder.py