this code is used to prevent duplicate submission on a Mautic form, examples:
- Prevent the same e-mail or phone number to be used in another submission (in the same form)
- prevent 2 people to subscribe to an event with the same phone number (or e-mail)
- prevent a coupon number to be used more than one time
watch the video on youtube: https://www.youtube.com/watch?v=xGjTe0Smup8