"no match found" exception when attempting to use addTextFrame

I'm trying to add text to an AutoShapeEx object, but the following code
throws an exception at the last line which reads "no match found":

PresentationEx presentation = new PresentationEx("c:\\myfile.pptx");
SlideEx coverSlide = presentation.getSlides().get(0);
ShapesEx coverShapes = coverSlide.getShapes();
int shapeIndex = coverShapes.addAutoShape(ShapeTypeEx.RECTANGLE, 10, 20, 30, 40);
AutoShapeEx ase = (AutoShapeEx)coverShapes.get(shapeIndex);

What is the problem?

Hi Peter,

Thanks for your interest in Aspose.Slides.
Please use following code snippet to add text to a Text Frame.

    //Instantiate PresentationEx class that represents PPTX
    PresentationEx pres = new PresentationEx("d:\\ppt\\example.pptx");
    SlideEx coverSlide = pres.getSlides().get(0);

    //Printing the total number of slides in the presentation

    //Fetcching all slide shapes
    ShapesEx coverShapes = coverSlide.getShapes();

    //Creating an auto shape
    int shapeIndex = coverShapes.addAutoShape(ShapeTypeEx.RECTANGLE, 100, 200, 66, 64);

    //Getting generated autoshape
    AutoShapeEx ase = (AutoShapeEx)coverShapes.get(shapeIndex);

    //Getting a text frame inside shape
    com.aspose.slides.pptx.TextFrameEx tx=ase.getTextFrame();

    //Accessing default paragraph and portion in text frame to add text.
    tx.getParagraphs().get(0).getPortions().get(0).setText("Sample Text Here Sample Text Here Sample Text Here ");

    //Writing to presentation
    pres.write(new FileOutputStream("D:/ppt/example.ppt") );
catch(Exception ex)

Thanks and Regards,