def by_site_protection_unit_id(self,site_protection_unit_id: str) -> SiteProtectionUnitItemRequestBuilder:
        """
        Provides operations to manage the siteProtectionUnits property of the microsoft.graph.backupRestoreRoot entity.
        param site_protection_unit_id: The unique identifier of siteProtectionUnit
        Returns: SiteProtectionUnitItemRequestBuilder
        """
        if site_protection_unit_id is None:
            raise TypeError("site_protection_unit_id cannot be null.")
        from .item.site_protection_unit_item_request_builder import SiteProtectionUnitItemRequestBuilder

        url_tpl_params = get_path_parameters(self.path_parameters)
        url_tpl_params["siteProtectionUnit%2Did"] = site_protection_unit_id
        return SiteProtectionUnitItemRequestBuilder(self.request_adapter, url_tpl_params)

        Provides operations to manage the siteProtectionUnits property of the microsoft.graph.backupRestoreRoot entity.
        param site_protection_unit_id: The unique identifier of siteProtectionUnit
        Returns: SiteProtectionUnitItemRequestBuilder
        
msgraph/generated/solutions/backup_restore/site_protection_units/site_protection_units_request_builder.py