Fix issue with backports import

pyproject.toml

@@ -87,6 +87,7 @@ module = [
     "palace.manager.api.controller.circulation_manager",
     "palace.manager.api.controller.loan",
     "palace.manager.api.controller.marc",
+    "palace.manager.api.controller.odl_notification",
     "palace.manager.api.discovery.*",
     "palace.manager.api.enki",
     "palace.manager.api.lcp.hash",

src/palace/manager/api/controller/odl_notification.py

@@ -44,7 +44,7 @@ def __init__(
         self.registry = registry
 
     def get_api(self, library: Library, loan: Loan) -> OPDS2WithODLApi:
-        return self.manager.circulation_apis[library.id].api_for_license_pool(
+        return self.manager.circulation_apis[library.id].api_for_license_pool(  # type: ignore[no-any-return]
             loan.license_pool
         )
 

src/palace/manager/opds/lcp/status.py

@@ -1,12 +1,18 @@
+import sys
 from enum import auto
 from functools import cached_property
 
-from backports.strenum import StrEnum
 from pydantic import AwareDatetime, Field, field_validator
 
 from palace.manager.core.exceptions import PalaceValueError
 from palace.manager.opds.base import BaseLink, BaseOpdsModel, ListOfLinks
 
+# TODO: Remove this when we drop support for Python 3.10
+if sys.version_info >= (3, 11):
+    from enum import StrEnum
+else:
+    from backports.strenum import StrEnum
+
 
 class Link(BaseLink):
     """

src/palace/manager/opds/odl/info.py

@@ -1,13 +1,19 @@
+import sys
 from enum import auto
 from functools import cached_property
 
-from backports.strenum import StrEnum
 from pydantic import AwareDatetime, Field, NonNegativeInt
 
 from palace.manager.opds.base import BaseOpdsModel, obj_or_set_to_set
 from palace.manager.opds.odl.odl import Protection, Terms
 from palace.manager.opds.opds import Price
 
+# TODO: Remove this when we drop support for Python 3.10
+if sys.version_info >= (3, 11):
+    from enum import StrEnum
+else:
+    from backports.strenum import StrEnum
+
 
 class Status(StrEnum):
     """