fix2

app.py

@@ -82,7 +82,7 @@ class BM25Index(InvertedIndex):
 
     @classmethod
     def build_from_documents(
-        cls: Type[BM25Index], documents: List[Document], avgdl: float, total_docs: int, k1: float = 0.9, b: float = 0.4
+        cls: Type["BM25Index"], documents: List[Document], avgdl: float, total_docs: int, k1: float = 0.9, b: float = 0.4
     ) -> BM25Index:
         # Assume run_counting() is defined to return counting object with relevant data
         counting = run_counting(documents, simple_tokenize)