Your MT4/MT5 EA.
Running on eToro.

void OnTick() {
  double ma_fast = iMA(NULL,0,8,0,MODE_EMA,
    PRICE_CLOSE,0);
  double ma_slow = iMA(NULL,0,21,0,MODE_EMA,
    PRICE_CLOSE,0);
  
  if(ma_fast > ma_slow && 
     OrdersTotal() == 0) {
    OrderSend(Symbol(), OP_BUY, 0.1,
      Ask, 3, Ask-100*Point,
      Ask+200*Point, "EA Buy");
  }
  if(ma_fast < ma_slow && 
     OrdersTotal() > 0) {
    OrderClose(OrderTicket(), 
      OrderLots(), Bid, 3);
  }
}

class EMA_Crossover(EToroBot):
    def __init__(self):
        self.fast_period = 8
        self.slow_period = 21
        self.sl_pips = 100
        self.tp_pips = 200
    
    def on_bar(self, symbol, prices):
        fast = ema(prices.close, 
                   self.fast_period)
        slow = ema(prices.close, 
                   self.slow_period)
        
        if fast > slow and not self.has_position:
            self.buy(symbol, 
              sl=self.sl_pips, tp=self.tp_pips)
        elif fast < slow and self.has_position:
            self.close_all(symbol)