def prepare_response(col_list: List[List[str]], prefix: List[str]=None) -> List[List[str]]:
    if (prefix is not None):
        col_list[0] = (prefix + col_list[0])
    return col_list
def prepare_response(col_list: List[List[str]], prefix: List[str]=None) -> List[List[str]]:
    if (prefix is not None):
        col_list[0] = (prefix + col_list[0])
    return col_list