fix: resolve all linting and formatting issues

- Convert Optional[str] to str | None syntax (Python 3.10+)
- Convert Union[str, bytes] to str | bytes syntax
- Fix isinstance checks to use union type syntax
- Apply consistent formatting across all integration test files

This should resolve all CI linting failures.

Author: jdrhyne

tests/integration/test_direct_api_integration.py

@@ -4,31 +4,29 @@
 test all Direct API methods against the live Nutrient DWS API.
 """
 
-from typing import Optional, Union
-
 import pytest
 
 from nutrient_dws import NutrientClient
 
 try:
     from . import integration_config  # type: ignore[attr-defined]
 
-    API_KEY: Optional[str] = integration_config.API_KEY
-    BASE_URL: Optional[str] = getattr(integration_config, "BASE_URL", None)
+    API_KEY: str | None = integration_config.API_KEY
+    BASE_URL: str | None = getattr(integration_config, "BASE_URL", None)
     TIMEOUT: int = getattr(integration_config, "TIMEOUT", 60)
 except ImportError:
     API_KEY = None
     BASE_URL = None
     TIMEOUT = 60
 
 
-def assert_is_pdf(file_path_or_bytes: Union[str, bytes]) -> None:
+def assert_is_pdf(file_path_or_bytes: str | bytes) -> None:
     """Assert that a file or bytes is a valid PDF.
 
     Args:
         file_path_or_bytes: Path to file or bytes content to check.
     """
-    if isinstance(file_path_or_bytes, (str, bytes)):
+    if isinstance(file_path_or_bytes, str | bytes):
         if isinstance(file_path_or_bytes, str):
             with open(file_path_or_bytes, "rb") as f:
                 content = f.read(8)

tests/integration/test_live_api.py

@@ -27,7 +27,7 @@ def assert_is_pdf(file_path_or_bytes: str | bytes) -> None:
     Args:
         file_path_or_bytes: Path to file or bytes content to check.
     """
-    if isinstance(file_path_or_bytes, (str, bytes)):
+    if isinstance(file_path_or_bytes, str | bytes):
         if isinstance(file_path_or_bytes, str):
             with open(file_path_or_bytes, "rb") as f:
                 content = f.read(8)

tests/integration/test_smoke.py

@@ -1,13 +1,11 @@
 """Basic smoke test to validate integration test setup."""
 
-from typing import Optional
-
 import pytest
 
 from nutrient_dws import NutrientClient
 
 # Type annotation for mypy
-API_KEY: Optional[str] = None
+API_KEY: str | None = None
 
 try:
     from . import integration_config  # type: ignore[attr-defined]