Question on query cost validator using validation_rules

[jfrank55]

I'm new to Ariadne and a python novice. I'm trying to complete a hands on learning session with Ariadne. I'm given a schema.graphql file (attached) with all the settings. I'm tasked with 2 things.

1. add some code to prevent a batched query with more that 5 queries.
2. if there are more than 5 queries in a batch query throw a 429 error.
   I'm given the code below to add. I assume i just change the '?' to 5. But i'm not sure how to incorporate this to schema.grpahql.
   I believe i need to add something to the PostResult and PostsResult functions, but i can't figure out what to add.
   Can someone help me to get the correct syntax? And where i need to make changes?

################################################
success, result = graphql_sync(
schema,
data,
context_value=request,
validation_rules=[cost_validator(maximum_cost=?)]
#################################################

schema.graphql.txt

)