Usage
fbad_read_creative(fbacc, id, by = c("account", "creative", "ad"),
fields = c("id", "name", "body", "title", "run_status", "actor_id",
"call_to_action_type", "follow_redirect", "image_crops", "image_file",
"image_hash", "image_url", "thumbnail_url", "link_url", "url_tags",
"object_id", "object_story_id", "object_story_spec", "object_type",
"object_url"))