Extentreports 5.1.1 ...Selenium with JAVA ..ExtentSparkReporter replacing the .html file for every run ...I need that to get appended

Question

I need only one single ExtentReport ..with all run results appended 


    private static ExtentTest test;
private static ExtentReports report;
private static ExtentSparkReporter sparkReporter;

@BeforeMethod
public void startTestMethod(Method testMethod) throws Exception {
sparkReporter = new ExtentSparkReporter("MyTestReport.html");
report = new ExtentReports();
report.attachReporter(sparkReporter);
test = report.createTest(testMethod.getName());
    
}

Everytime I run my testcase .."MyTestReport.html" is getting replaced ...but I need that to be appended with new test result ..