How to move a sketchPoint of a tangent handle of fitPoint in sketchFittedSpline?

[NaokiKita]

Hi, I'm new to Fusion 360.

I would like to update the coordinate of the startSketchPoint of the tangent handle to (newX, 0, 0) as shown below.

curve = sketch.sketchCurves.sketchFittedSplines.add(points)
tHandle = curve.activateTangentHandle(curve.fitPoints[-1])
tHandle.startSketchPoint.worldGeometry.set(newX, 0, 0)

However, the coordinate won't be updated.

Could anyone help me?

Thanks in advance.