fix: resolve environment-dependent ty failure on python 3.10

Author: raederan

pyproject.toml

@@ -114,6 +114,9 @@ dev = [
     "deptry>=0.25.1",
     # optional-extra backends installed in dev so their modules type-check
     "boto3",
+    # installed unconditionally (runtime dep is <3.11 only) so ty resolves
+    # the version-guarded import in custom_types.py on every python version
+    "backports.strenum",
     # docs
     "zensical>=0.0.46",
     "mkdocstrings-python>=1.0.3",

src/osw/custom_types.py

@@ -6,8 +6,7 @@
 from pydantic.v1.validators import path_validator  # , path_exists_validator
 
 if sys.version_info < (3, 11):
-    # not installed in envs >=3.11, hence unresolvable for ty there
-    from backports.strenum import StrEnum  # ty: ignore[unresolved-import]
+    from backports.strenum import StrEnum
 else:
     from enum import StrEnum  # noqa: F401