public AttributeTable Remove(DerObjectIdentifier attrType)
        {
            AttributeTable newTable = new AttributeTable(attributes);

            newTable.attributes.Remove(attrType);

            return newTable;
        }
        /**
         * Return a new table with the passed in attribute added.
         *
         * @param attrType
         * @param attrValue
         * @return
         */
        public AttributeTable Add(DerObjectIdentifier attrType, Asn1Encodable attrValue)
        {
            AttributeTable newTable = new AttributeTable(attributes);

            newTable.AddAttribute(new Attribute(attrType, new DerSet(attrValue)));

            return newTable;
        }