partial class Examples
{
  public static Rhino.Commands.Result AddNurbsCurve(Rhino.RhinoDoc doc)
  {
    Rhino.Collections.Point3dList points = new Rhino.Collections.Point3dList(5);
    points.Add(0, 0, 0);
    points.Add(0, 2, 0);
    points.Add(2, 3, 0);
    points.Add(4, 2, 0);
    points.Add(4, 0, 0);
    Rhino.Geometry.NurbsCurve nc = Rhino.Geometry.NurbsCurve.Create(false, 3, points);
    Rhino.Commands.Result rc = Rhino.Commands.Result.Failure;
    if (nc != null && nc.IsValid)
    {
      if (doc.Objects.AddCurve(nc) != Guid.Empty)
      {
        doc.Views.Redraw();
        rc = Rhino.Commands.Result.Success;
      }
    }
    return rc;
  }
}

import Rhino
import scriptcontext
import System.Guid

def AddNurbsCurve():
    points = Rhino.Collections.Point3dList(5)
    points.Add(0, 0, 0)
    points.Add(0, 2, 0)
    points.Add(2, 3, 0)
    points.Add(4, 2, 0)
    points.Add(4, 0, 0)

    nc = Rhino.Geometry.NurbsCurve.Create(False, 3, points)
    rc = Rhino.Commands.Result.Failure
    if nc and nc.IsValid:
        if scriptcontext.doc.Objects.AddCurve(nc)!=System.Guid.Empty:
            scriptcontext.doc.Views.Redraw()
            rc = Rhino.Commands.Result.Success
    return rc

if __name__=="__main__":
    AddNurbsCurve()