diff --git a/monkey/infection_monkey/utils/dir_utils.py b/monkey/infection_monkey/utils/dir_utils.py
index 704556335..2fd29af9e 100644
--- a/monkey/infection_monkey/utils/dir_utils.py
+++ b/monkey/infection_monkey/utils/dir_utils.py
@@ -6,7 +6,9 @@ def get_all_regular_files_in_directory(dir_path: Path) -> List[Path]:
     return filter_files(dir_path.iterdir(), [lambda f: f.is_file()])
 
 
-def filter_files(files: Iterable[Path], file_filters: List[Callable[[Path], bool]]):
+def filter_files(
+    files: Iterable[Path], file_filters: Iterable[Callable[[Path], bool]]
+) -> List[Path]:
     filtered_files = files
     for file_filter in file_filters:
         filtered_files = [f for f in filtered_files if file_filter(f)]
@@ -14,16 +16,16 @@ def filter_files(files: Iterable[Path], file_filters: List[Callable[[Path], bool
     return filtered_files
 
 
-def file_extension_filter(file_extensions: Set):
-    def inner_filter(f: Path):
+def file_extension_filter(file_extensions: Set) -> Callable[[Path], bool]:
+    def inner_filter(f: Path) -> bool:
         return f.suffix in file_extensions
 
     return inner_filter
 
 
-def is_not_symlink_filter(f: Path):
+def is_not_symlink_filter(f: Path) -> bool:
     return not f.is_symlink()
 
 
-def is_not_shortcut_filter(f: Path):
+def is_not_shortcut_filter(f: Path) -> bool:
     return f.suffix != ".lnk"