def METHOD_NAME(res: list, key: str) -> list:
    """
    Unpacks a query result list (i.e., list of dicts) into a list of 
    unique values for the given dict key.
    """    
    res_list =  list(set([r.get(key) for r in res]))
    res_list = [v for v in res_list if v is not None]
    return res_list