我正在尝试使用PartiQL语法向DynamoDB中的现有列表属性追加值。
项目的主键包括：

pk = userId

sk = happeningId

table_name = test_table
userId = "user09hfh47egd53tgd"
happeningId = "happ09hdg2536dget7354tdg"
contactId = "C0003"
decision = "accept"

if decision == "accept":

    stmt = f"UPDATE \"{table_name}\" SET accept = list_append(accept, :'{contactId}') WHERE pk='{userId}' AND sk='{happeningId}'"
    print(stmt)
    resp = dynamodb_client.execute_statement( Statement=stmt )
else:
    stmt = f"UPDATE \"{table_name}\" SET cancel = list_append(cancel, :'{contactId}') WHERE pk='{userId}' AND sk='{happeningId}'"
    print(stmt)
    resp = dynamodb_client.execute_statement( Statement=stmt )

最后一个字符串如下所示

UPDATE "test_table" SET accept = list_append(accept, :'C0003') WHERE pk='user09hfh47egd53tgd' AND sk='happ09hdg2536dget7354tdg'

当我尝试运行我的代码时，我收到以下错误消息：

ClientError: An error occurred (ValidationException) when calling the ExecuteStatement operation: Statement wasn't well formed, can't be processed: Unexpected term

有人知道我做错了什么吗？