flash error on form validation error

app/routes.py

@@ -6,12 +6,14 @@ from datetime import datetime, timedelta
 @app.route('/', methods=['GET', 'POST'])
 def download():
     form = DownloadForm()
-    if form.validate_on_submit():
+    if request.method == 'GET':
-        flash('The download should start immediately.')
-        return render_template('download.html', form=form, filename='test.mp3')
-    elif request.method == 'GET':
         form.date.data = datetime.now() - timedelta(hours = 1)
         form.length.data = 60
+    elif form.validate_on_submit():
+        flash('The download should start immediately.')
+        return render_template('download.html', form=form, filename='test.mp3')
+    else:
+        flash('Error')
     return render_template('download.html', form=form)
 
 @app.route('/download_file/<path:filename>')