Update app.py

app.py

@@ -33,7 +33,7 @@ def my_custom_tool(arg1:str, arg2:int)-> str: #it's import to specify the return
 import requests
 
 @tool
-def get_book():
+def get_book() -> List[PotterBook]
     """A tool that fetches the Harry Potter books with information about them.
     Args:
     """
@@ -43,7 +43,7 @@ def get_book():
     return libros
 
 @tool
-def filter_book(libro, campo, valor, operador='=='):
+def filter_book(libro, campo, valor, operador='==') -> List:
     """
     Filtra libros según un campo, valor y operador especificados
     operadores permitidos: ==, >, <, >=, <=, contains