protected override DateTime?Deserialize(string value, Type objectType)
 {
     return(value.IsNullOrEmpty() ? null : ( DateTime? )DateTimeConverter.ConvertFrom(value));
 }
 protected override DateTime?Deserialize(JToken value, Type objectType)
 {
     return(value.IsNull() || value.Type.Equals(JTokenType.Null) ? null : (DateTime?)DateTimeConverter.ConvertFrom(value));
 }