Update app.py

app.py

@@ -13,7 +13,8 @@ def get_servo_list(fileid):
 
 @app.route('/')
 def main():
-    return 'a very nice page, you must admit, heres a list of files:' + os.listdir('.') 
+    files = os.listdir('.')
+    return f'a very nice page, you must admit, heres a list of files: {files}'
 
 @app.route('/input')
 def apirequests():