abstract class for generating ID's to Attribute Names and Lists of Attrbute Names
public Integer Get_Attribute_ID( Ada.Strings.Unbounded.Unbounded_String Name);
public Integer Get_Attribute_ID
returns the corresponding ID of an Attribute Name
public Integer Get_Attribute_List_ID( OpenCAGE.General.String_List.List Attributes);
public Integer Get_Attribute_List_ID
returns the ID of the Set of Attributes represented by Attribute List