TradingView - Pine Script Demo Indicator Code

Hello dear my friend,

I have some PREMIUM indicators at TradingView, which user needs to have invitation from me to use these indicator.
it is very difficult for me to give free trial to lots of people.

my indicators are multilanguage, Turkish and English

I need a code for pine script

I will put to my real indicator and combine for demo indicator.
This indicator will stop indicator to work with all symbols at TradingView

it will work just;
TVC:DXY
CRYPTOCAP:USDT.D
BISTMIXED:XU100

and if user try to use it at different symbol at Tradingview for example at BTCUSDT
it will watermark at the buttom center of the chart like this with the language that user sellect at indicator.




At the DXY, USDT.D and XU100 chart, it will not give this watermark
indicator will work and just give watermark that, it is a demo version