[BrandonGiesing]

Originally Posted by chaley

Pontificating aside, one can do what you want with a template-language template but with 5,000 tags it would be excruciatingly slow. This python template doesn't have that problem.

python:
def evaluate(book, context):
	field = 'tags'

	# Get the previously computed set of acceptable items, if it exists
	all_names_over_count = context.globals.get('all_names_over_count')
	if all_names_over_count is None:
		db = context.db.new_api
		all_names_over_count = set()
		counts_by_item = db.get_usage_count_by_id(field)
		for item,count in counts_by_item.items():
			if count > 5:
				all_names_over_count.add(db.get_item_name(field, item))
		context.globals['all_names_over_count'] = all_names_over_count

	# Check if the current book has any of the acceptable items
	item_names_in_book = []
	for name in book.get(field):
		if name in all_names_over_count:
			item_names_in_book.append(name)
	return ':@:'.join(item_names_in_book)

Code isn't working, throws the error:

EXCEPTION: Error in function evaluate on line 8 : AttributeError - 'NoneType' object has no attribute 'new_api'