Record Batch.

Ninth class — capstone. Process a list of records: valid and invalid. Use small helpers + try/except.

Idea: for each record try to compute BMI (or a similar metric). On ValueError increase a fail counter. On success — print the result and increase ok.

You combine: small functions, checks, raise/catch, a loop. That is real batch style.

Common mistake: one huge try around the whole loop (you lose which rows passed); or stopping on the first error when the task wants to count all.