added type hints

app.py

@@ -41,7 +41,7 @@ def extract_text_from_pdf(pdf_path: str) -> str:
     return text
 
 @tool
-def extract_entities(text, desired_entities):
+def extract_entities(text: str, desired_entities: list) -> list:
     """A tool that extracts entities from a text using spaCy.
     Args:
         text: A string representing the text to extract entities from.