fix _exit()

Author: glaukiol1

os/os.module.go

@@ -224,18 +224,10 @@ func _exit(self py.Object, args py.Tuple) (py.Object, error) { // can never retu
 		os.Exit(0)
 	}
 	arg, ok := args[0].(py.Int)
-	if !ok { ...  handle error ... }
-		_ec, err := py.GetInt(args[0])
-		if err != nil {
-			os.Exit(1)
-		}
-		exit_code, err := _ec.GoInt()
-		if err != nil {
-			os.Exit(1)
-		}
-		os.Exit(exit_code)
-	}
-	os.Exit(1)
+	if !ok {
+		return nil, py.ExceptionNewf(py.TypeError, "expected int (pos 1), not "+args[0].Type().Name)
+	}
+	os.Exit(int(arg))
 	return nil, nil
 }