Delete duplicate points on Nurbs curve

I need to remove the duplicate points on curve. How to do with Rhinocommon?

RhinoCommon does not have a function that will removed stacked control points. Deleting is difficult because you cannot always just delete them without changing the curve significantly.

If your looking for a way to find them, then this might help.

public static bool IsStackedControlPointsCurve(NurbsCurve nc)
{
  var rc = false;
  if (null != nc && nc.IsValid)
  {
    for (var i = 0; i < nc.Points.Count - 1; i++)
    {
      var cv0 = nc.Points[i];
      var cv1 = nc.Points[i + 1];
      var dist = cv0.Location.DistanceTo(cv1.Location);
      if (dist < RhinoMath.ZeroTolerance)
      {
        rc = true;
        break;
      }
    }
  }
  return rc;
}

I cannot use CullDuplicate function?

I want to know this too.
why the command “_RemoveControlPoint” can do it ?
I was very confused .