How to get Dataset form custom table using API in Kentico

Here are the sample codes for getting the Data(DataSet) from Custom Table:
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CMS.SiteProvider.CustomTableItemProvidertp = new 
CMS.SiteProvider.CustomTableItemProvider(CMS.CMSHelper.CMSContext.CurrentUser);
DataSet ds = tp.GetItems("CustomTableCodeName", "whereCondition", "OrderBy");.