diff --git a/rwx/fs/__init__.py b/rwx/fs/__init__.py
index 21ead50..b320ed2 100644
--- a/rwx/fs/__init__.py
+++ b/rwx/fs/__init__.py
@@ -9,12 +9,18 @@ from rwx import ps
 CHARSET = "UTF-8"
 
 
-def create_image(file_path: str, size_bytes: int) -> None:
-    """Create a virtual device image file."""
+def create_image(file_path: Path, size_bytes: int) -> None:
+    """Create a virtual device image file.
+
+    :param file_path: target image file
+    :type file_path: Path
+    :param size_bytes: virtual volume
+    :type size_bytes: int
+    """
     ps.run(
         ("qemu-img", "create"),
         ("-f", "qcow2"),
-        (file_path, str(size_bytes)),
+        (str(file_path), str(size_bytes)),
     )