diff --git a/conversions/decimal_to_binary.py b/conversions/decimal_to_binary.py
index ad4ba1667..e6821c09b 100644
--- a/conversions/decimal_to_binary.py
+++ b/conversions/decimal_to_binary.py
@@ -1,7 +1,7 @@
 """Convert a Decimal Number to a Binary Number."""
 
 
-def decimal_to_binary(num):
+def decimal_to_binary(num: int) -> str:
 
     """
         Convert a Integer Decimal Number to a Binary Number as str.