PyMISP tags() method slow response on MISP ver 2.4.131 with 3k tags

The pymisp doc for the tags() method says simply "Get the list of existing tags". I expected this method to be implemented as roughly "select * from misp.tags;" at the database and return answers quickly. Instead, our version 2.4.131 system requires about 100 seconds to return a list of about 3,300 tags, using the default pythonify=False option.

I checked the database where I see queries like this running:

SELECT COUNT(*) AS `count` FROM `misp`.`attributes` AS `Attribute` 
LEFT JOIN `misp`.`events` AS `Event` ON (`Attribute`.`event_id` = `Event`.`id`) 
LEFT JOIN `misp`.`sharing_groups` AS `SharingGroup` ON (`Attribute`.`sharing_group_id` = `SharingGroup`.`id`) 
LEFT JOIN `misp`.`objects` AS `Object` ON (`Attribute`.`object_id` = `Object`.`id`)  
WHERE `Attribute`.`id` IN (39717, 39730, 39751, ..

Here's a sample Tag from the response list. Interestingly, the database column 'numerical_value' is not returned, but other fields are returned. I cannot find any explanation of fields "count" and "attribute_count" but I bet those are the usages of this tag:

{"id": "1221", "name": "malware_classification:malware-category=\"Botnet\"", "colour": "#22681c", "exportable": true,
  "org_id": "0", "hide_tag": false, "user_id": "0", "count": "0", "attribute_count": "0", "favourite": false}

I think the root cause of this issue is probably documentation, not software. If I'm right in guessing that the tags() method's results contain stats for every tag about its usage in events and attributes, then I'll be glad to submit a PR with an extended docstring for the tags() method.

Start at the PyMISP tags() method and review its current docstring and returned fields. Clarify what count and attribute_count represent, whether the response includes usage statistics, and the effect of pythonify=False. Done means the method documentation accurately explains the response and the reason a large tag list may be slow.