C# code from the Model class below

public string Svg { get; set; }

// Creates a workbook with the selected shape.
// The SVG content is written to the Svg property.
public ExcelPackage CreateWorkbookWithShape(string shapeStyleName)
{
    Enum.TryParse(shapeStyleName, out eShapeStyle shapeStyle);
    var package = new ExcelPackage();
    var ws = package.Workbook.Worksheets.Add("Shapes to SVG");
    var shape = ws.Drawings.AddShape(shapeStyleName, shapeStyle);
    shape.Text = shapeStyleName;
    shape.SetPosition(100, 100);
    shape.SetSize(600, 600);
    Svg = shape.ToSvg();
    return package;
}