/// <summary>
        /// This is the method that actually does the work.
        /// </summary>
        /// <param name="DA">The DA object is used to retrieve from inputs and store in outputs.</param>
        protected override void SolveInstance(IGH_DataAccess DA)
        {
            IMesh      mesh   = new IMesh();
            double     length = 1;
            List <int> eKeys  = new List <int>();

            DA.GetData(0, ref mesh);
            DA.GetDataList(1, eKeys);
            DA.GetData(2, ref length);

            IMesh dM = IModifier.ExtrudeTwoDimensionalElements(mesh, eKeys, length);

            DA.SetData(0, dM);
        }