Update app.py

app.py

@@ -48,6 +48,11 @@ def filter_book(libro, campo, valor, operador='==') -> List:
     """
     Filtra libros según un campo, valor y operador especificados
     operadores permitidos: ==, >, <, >=, <=, contains
+    Args:
+        libro: name o text title of the book we are looking for
+        campo: field of the book we are looking for
+        valor: value to compair with the field
+        operador: kind of compartive that we want to have over the field and de value 
     """
     if operador == 'contains':
         return [libro for libro in libros if valor.lower() in str(getattr(libro, campo)).lower()]