diff --git a/main.py b/main.py
index 24ecd580d2e6a895fe5d2ef0e15d320296b7aef7..42b903c1aa43f5def3772ac68b9a96ca5c3889f2 100644
--- a/main.py
+++ b/main.py
@@ -38,13 +38,13 @@ defaults = [10,15,20,0]
 
 def clear():
  
-    # for windows
-    if os.name == 'nt':
-        _ = system('cls')
+    # for windows, os.name is 'nt'
+    if os.name == "nt":
+        os.system('cls')
  
     # for mac and linux(here, os.name is 'posix')
     else:
-        _ = system('clear')
+        os.system('clear')
 
 def calculate():