Add return type.

run.py

@@ -1,3 +1,4 @@
+from typing import Generator
 from tagger.interrogator import Interrogator
 from PIL import Image
 from pathlib import Path
@@ -60,7 +61,7 @@ def image_interrogate(image_path: Path):
         return Interrogator.postprocess_tags(result[1], threshold=args.threshold)
     return Interrogator.postprocess_tags(result[1], threshold=args.threshold, escape_tag=True, replace_underscore=True)
 
-def explore_files(folder_path: Path):
+def explore_image_files(folder_path: Path) -> Generator[Path, None, None]:
     """
     Explore files by folder path
     """
@@ -68,13 +69,12 @@ def explore_files(folder_path: Path):
         if path.is_file() and path.suffix in ['.png', '.jpg', '.jpeg', '.webp']:
             yield path
         elif args.recursive and path.is_dir():
-            yield from explore_files(path)
+            yield from explore_image_files(path)
 
 if args.dir:
     root_path = Path(args.dir)
-    for file_path in explore_files(root_path):
-        image_path = Path(file_path)
-        caption_path = image_path.parent / f'{file_path.stem}{args.ext}'
+    for image_path in explore_image_files(root_path):
+        caption_path = image_path.parent / f'{image_path.stem}{args.ext}'
 
         if caption_path.is_file() and not args.overwrite:
             # skip if caption exists