Update pnv.js

pnv.js

@@ -45,8 +45,8 @@ let options = {
   args: args
 };
  
-PythonShell.run(src, options, async function (err, results) {
-  if (err) throw err;
+PythonShell.run(src, options, function (err, results) {
+  if (err) reject(err);
   // results is an array consisting of messages collected during execution
   //console.log('results: %j', results);
   resolve(results) ;