public static Result<string> CreateCustomField(string apiKey, string listID, string fieldName, CampaignMonitorAPIWrapper.CampaignMonitorAPI.SubscriberFieldDataType dataType, string options)
        {
            CampaignMonitorAPIWrapper.CampaignMonitorAPI.api _api = new CampaignMonitorAPI.api();

            object o = _api.CreateListCustomField(apiKey, listID, fieldName, dataType, options);

            if (o is CampaignMonitorAPI.Result)
                return new Result<string>((CampaignMonitorAPI.Result)o, "");
            else
                return new Result<string>(0, "Success", Convert.ToString(o));
        }