| using System; | 
 | using System.Collections.Generic; | 
 | using System.Linq; | 
 | using System.Text; | 
 |  | 
 | namespace OfficeOpenXml.FormulaParsing.Utilities | 
 | { | 
 |     public static class ExtensionMethods | 
 |     { | 
 |         public static void IsNotNullOrEmpty(this ArgumentInfo<string> val) | 
 |         { | 
 |             if (string.IsNullOrEmpty(val.Value)) | 
 |             { | 
 |                 throw new ArgumentException(val.Name + " cannot be null or empty"); | 
 |             } | 
 |         } | 
 |  | 
 |         public static void IsNotNull<T>(this ArgumentInfo<T> val) | 
 |             where T : class | 
 |         { | 
 |             if (val.Value == null) | 
 |             { | 
 |                 throw new ArgumentNullException(val.Name); | 
 |             } | 
 |         } | 
 |  | 
 |         public static bool IsNumeric(this object obj) | 
 |         { | 
 |             if (obj == null) return false; | 
 |             return (obj.GetType().IsPrimitive || obj is double || obj is decimal || obj is System.DateTime || obj is TimeSpan); | 
 |         } | 
 |     } | 
 | } |