How can I create a new campaign using a Mailchimp template via Python Mailchimp API?

Question

I built an email template via the Mailchimp drag and drop tool. I'm trying to now create a new email campaign using the template as the new campaign content but it doesn't seem to be working. I chatted with Mailchimp support several times and they also didn't know why it isn't working and had no solutions.

I get no errors. It successfully creates a new campaign but uses default content (not the desired email template I built). I use actual variables in my code for api_key, server, email address, and templateID.

Via the Mailchimp API documentation, this is my code:

import mailchimp_marketing as MailchimpMarketing
from mailchimp_marketing.api_client import ApiClientError

mailchimp = MailchimpMarketing.Client()
mailchimp.set_config({
  "api_key": "api-key",
  "server": "server-num"
    })

try:
    # Create a new campaign
    campaign = mailchimp.campaigns.create({
      "type": "regular",
      "settings": {
        "subject_line": "Test Email Subject Line",
        "reply_to": "email@email.com",
        "from_name": "Sender Name"
      }
    })

    # Set campaign content
    campaign_content = mailchimp.campaigns.set_content(campaign['id'], {
      "template": {
        "id": templateID
      }
    })

    print('Campaign Created:', campaign['id'])

except ApiClientError as error:
    print("Error: {}".format(error.text))

Mailchimp Marketing API Documentation: https://mailchimp.com/developer/marketing/guides/quick-start/