Get Douyin creative keyword related items

Returns Douyin videos related to a specific hot keyword in a category. Send tag_id (Category ID, required, does NOT support 0=all), keyword (Keyword (get from fetch_content_creative_keywords)), end_date (End date YYYYMMDD (must be a Sunday only when period=7*..); optional period. end_date: End date YYYYMMDD. Must be a Sunday only when period=7; any day for period=1/3.