/// An empty non-static graph class.

     /// An empty non-static graph class.

     /// This class provides everything that \c StaticGraphSkeleton

     /// This class provides everything that \c StaticGraphSkeleton

     /// with additional functionality which enables to build a

     /// with additional functionality which enables to build a

     /// graph from scratch.

     /// graph from scratch.

     {

     {

     public:

     public:

       /// Defalult constructor.

       /// Defalult constructor.

       /// Defalult constructor.

       /// Defalult constructor.

       ///

       ///

       ///Add a new node to the graph.

       ///Add a new node to the graph.

       /// \return the new node.

       /// \return the new node.

       ///

       ///

       Node addNode() { return INVALID; }

       Node addNode() { return INVALID; }

     /// An empty erasable graph class.

     /// An empty erasable graph class.

     /// This class is an extension of \c GraphSkeleton. It also makes it

     /// This class is an extension of \c GraphSkeleton. It also makes it

     /// possible to erase edges or nodes.

     /// possible to erase edges or nodes.

     {

     {

     public:

     public:

       /// Defalult constructor.

       /// Defalult constructor.

       /// Defalult constructor.

       /// Defalult constructor.