Implement closing positions

core/exchanges/__init__.py

@@ -218,6 +218,10 @@ class BaseExchange(ABC):
     def get_all_positions(self):
         pass
 
+    @abstractmethod
+    def close_position(self, side, symbol):
+        pass
+
     @abstractmethod
     def close_all_positions(self):
         pass

core/exchanges/alpaca.py

@@ -130,3 +130,9 @@ class AlpacaExchange(BaseExchange):
             item["unrealized_pl"] = float(item["unrealized_pl"])
             items.append(item)
         return items
+
+    def close_position(self, side, symbol):
+        pass
+
+    def close_all_positions(self):
+        pass