fix convert

order.py

@@ -81,6 +81,19 @@ class OrderManager:
             price=price,
             size=size,
         )
+    def convert(self, symbol: str, size: int):
+        if symbol == "VALE":
+            target = "VALBZ"
+            self.future_positions["VALE"] -= size
+            self.future_positions["VALBZ"] += size
+            self.positions["VALE"] -= size
+            self.positions["VALBZ"] += size
+        return self.exchange.send_convert_message(
+            order_id=self._next_order(),
+            symbol=symbol,
+            dir="BUY",
+            size=size,
+        )
 
     def buy(self, symbol: str, price: int, size: int):
         return self._attempt_send(