diff --git a/tools/tools.py b/tools/tools.py
index c277cc6..69e9b0e 100644
--- a/tools/tools.py
+++ b/tools/tools.py
@@ -5,7 +5,7 @@ import sys
 from typing import Any
 
 
-def get_script_dir(follow_symlinks=True):
+def get_script_dir(follow_symlinks: bool = True) -> str:
     """return path of the executed script"""
     if getattr(sys, 'frozen', False):
         path = os.path.abspath(sys.executable)
@@ -29,7 +29,7 @@ def compare(a: Any, b: Any) -> int:
 def human_readable_time_from_delta(delta: datetime.timedelta) -> str:
     time_str = ""
     if delta.days > 0:
-        time_str += "%d days, " % delta.days
+        time_str += "%d day%s, " % (delta.days, "s" if delta.days > 1 else "")
 
     if delta.seconds > 3600:
         time_str += "%02d:" % (delta.seconds // 3600)