Update os/os.module.go

Co-authored-by: Sebastien Binet <[email protected]>

Author: glaukiol1

os/os.module.go

@@ -97,9 +97,11 @@ func chdir(self py.Object, args py.Tuple) (py.Object, error) {
 // getenv returns the value of the environment variable key.
 // If no such environment variable exists and a default value was provided, that value is returned.
 func getenv(self py.Object, args py.Tuple) (py.Object, error) {
-	var key py.Object      // key to search for
-	var default_ py.Object // return when not found
-	var err error          // error obj
+	var (
+		key py.Object
+		dflt = py.None
+		err error
+	)
 
 	if len(args) == 1 {
 		if objectIsString(args[0]) {