solve without enemies, initial impl. still requires factoring out

app/models/bundle.py

@@ -14,6 +14,16 @@ class Bundle(BaseModel):
     items: List[Item]
     type: str
 
+    def find_items(self, requested_items_ids: [int]) -> [Item]:
+        found_items = []
+
+        for item in self.items:
+            if item.id in requested_items_ids:
+                found_items.append(item)
+
+        return found_items
+
+
     def tif(self, irt_model: IRTModel, theta: float) -> float:
         return TestInformationFunction(irt_model).calculate(self.items, theta=theta)