如何通过openxml获取形状中文本的字体大小？

using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Presentation;
using DocumentFormat.OpenXml.Wordprocessing;

public class OpenXmlHelper
{
    public static void GetShapeTextFontSize(string filePath)
    {
        using (PresentationDocument presentationDoc = PresentationDocument.Open(filePath, false))
        {
            PresentationPart presentationPart = presentationDoc.PresentationPart;
            foreach (SlidePart slidePart in presentationPart.SlideParts)
            {
                foreach (Shape shape in slidePart.Slide.Descendants<Shape>())
                {
                    if (shape.TextBody != null)
                    {
                        foreach (TextParagraph paragraph in shape.TextBody.Descendants<TextParagraph>())
                        {
                            foreach (TextRun textRun in paragraph.Descendants<TextRun>())
                            {
                                if (textRun.RunProperties != null && textRun.RunProperties.FontSize != null)
                                {
                                    double fontSize = Convert.ToDouble(textRun.RunProperties.FontSize.Val) / 100;
                                    Console.WriteLine("Shape: {0}, Font Size: {1}", shape.InnerText, fontSize);
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}