Support both position modes on OKX

freqtrade/exchange/exchange.py

@@ -198,6 +198,7 @@ class Exchange:
 
         if self.trading_mode != TradingMode.SPOT:
             self.fill_leverage_tiers()
+        self.additional_exchange_init()
 
     def __del__(self):
         """
@@ -294,6 +295,14 @@ class Exchange:
         """exchange ccxt precisionMode"""
         return self._api.precisionMode
 
+    def additional_exchange_init(self) -> None:
+        """
+        Additional exchange initialization logic.
+        .api will be available at this point.
+        Must be overridden in child methods if required.
+        """
+        pass
+
     def _log_exchange_response(self, endpoint, response) -> None:
         """ Log exchange responses """
         if self.log_responses:
@@ -944,6 +953,7 @@ class Exchange:
 
     def _get_params(
         self,
+        side: BuySell,
         ordertype: str,
         leverage: float,
         reduceOnly: bool,
@@ -973,7 +983,7 @@ class Exchange:
             dry_order = self.create_dry_run_order(pair, ordertype, side, amount, rate, leverage)
             return dry_order
 
-        params = self._get_params(ordertype, leverage, reduceOnly, time_in_force)
+        params = self._get_params(side, ordertype, leverage, reduceOnly, time_in_force)
 
         try:
             # Set the precision for amount and price(rate) as accepted by the exchange