code: def stack_template_url(bucket_name, blueprint, endpoint):
      
      key_name = stack_template_key_name(blueprint)
      return "%s/%s/%s" % (endpoint, bucket_name, key_name)
docs: Produces an s3 url for a given blueprint.
  
      Args:
          bucket_name (string): The name of the S3 bucket where the resulting
              templates are stored.
          blueprint (:class:`stacker.blueprints.base.Blueprint`): The blueprint
              object to create the URL to.
          endpoint (string): The s3 endpoint used for the bucket.
  
      Returns:
          string: S3 URL.