fix: ensure Python version compatibility for union types

- Replace bytes | None with Union[bytes, None] for broader compatibility
- Replace str | None with Union[str, None] in examples
- Add noqa: UP007 comments to suppress linter preference for newer syntax
- Ensures compatibility with Python environments that don't support PEP 604 unions
- Fixes test failure: 'Unable to evaluate type annotation bytes | None'

All File parameter tests continue to pass (13/13) across Python versions.

Author: oyiz-michael

examples/event_handler_rest/src/file_parameter_example.py

@@ -4,7 +4,7 @@
 
 from __future__ import annotations
 
-from typing import Annotated
+from typing import Annotated, Union
 
 from aws_lambda_powertools.event_handler import APIGatewayRestResolver
 from aws_lambda_powertools.event_handler.openapi.params import File, Form
@@ -23,7 +23,7 @@ def upload_single_file(file: Annotated[bytes, File(description="File to upload")
 def upload_file_with_metadata(
     file: Annotated[bytes, File(description="File to upload")],
     description: Annotated[str, Form(description="File description")],
-    tags: Annotated[str | None, Form(description="Optional tags")] = None,
+    tags: Annotated[Union[str, None], Form(description="Optional tags")] = None,  # noqa: UP007
 ):
     """Upload a file with additional form metadata."""
     return {
@@ -63,7 +63,7 @@ def upload_small_file(file: Annotated[bytes, File(description="Small file only",
 @app.post("/upload-optional")
 def upload_optional_file(
     message: Annotated[str, Form(description="Required message")],
-    file: Annotated[bytes | None, File(description="Optional file")] = None,
+    file: Annotated[Union[bytes, None], File(description="Optional file")] = None,  # noqa: UP007
 ):
     """Upload with an optional file parameter."""
     return {

tests/functional/event_handler/_pydantic/test_file_multipart_comprehensive.py

@@ -6,7 +6,7 @@
 
 import base64
 import json
-from typing import Annotated
+from typing import Annotated, Union
 
 from aws_lambda_powertools.event_handler import APIGatewayRestResolver
 from aws_lambda_powertools.event_handler.openapi.params import File, Form
@@ -286,7 +286,7 @@ def test_optional_file_parameter():
     @app.post("/upload")
     def upload_file(
         message: Annotated[str, Form(description="Required message")],
-        file: Annotated[bytes | None, File(description="Optional file")] = None,
+        file: Annotated[Union[bytes, None], File(description="Optional file")] = None,  # noqa: UP007
     ):
         return {"has_file": file is not None, "file_size": len(file) if file else 0, "message": message}