如何修复在多人或组字段中添加用户时 SharePoint 中的错误（仅限人员）

我正在尝试在 Sharepoint 列表中的多人或组字段（仅限人员）中添加多个用户，但我收到以下错误消息

“从 JSON 读取器读取时发现意外的‘PrimitiveValue’节点。预期是‘StartObject’节点。”

我已使用 REST 调用在 Sharepoint 列表中添加项目，当我在其余调用中删除多人列时，项目会正确添加。

$scope.formData = { Title: $scope.codeNumber, SBMTestId:{ "results": [17,15] } }
                var data = JSON.stringify($scope.formData);
                var listName = "Test";
                data = data.replace(/[{}]/g, '');
                var datavalue = "{__metadata:{'type':'SP.Data.TestListItem'}," + data + "}";
                $http({
                    url: _spPageContextInfo.webAbsoluteUrl + "/_api/web/lists/GetByTitle('" + listName + "')/items",
                    method: "POST",
                    headers: {
                        "Accept": "application/json;odata=verbose",
                        "Content-Type": "application/json;odata=verbose",
                        "X-RequestDigest": $("#__REQUESTDIGEST").val(),
                        "X-HTTP-Method": "POST"
                    },
                    data: datavalue
                }).then(function (response) {
           alert("Go on!");

        }, function (response) {
                    alert("Something is wrong. Please try after sometimes");
                }); 

错误信息如下：

data:
  error:
    code:"-1, Microsoft.SharePoint.Client.InvalidClientQueryException"
    message:
    lang:"en-US"
    value:"An unexpected 'PrimitiveValue' node was found when reading from the JSON reader. A 'StartObject' node was expected."

尝试下面的 JSON 数据格式。

{
            "__metadata": { "type": "SP.Data.MyList2ListItem" },
            "Title": "RestApiCreated",
            "MultiUsersId": { "results": ["12", "23"] }
        }