X++ code to validate only numbers in string

static void TextBuffer_regularExpression(Args _args)
{
    TextBuffer txt = new TextBuffer();
    str msg = "98797897";
    ;


    txt.setText(msg);
    txt.regularExpressions(true);   // activate regular expr in search


     // Regular expression to validate only digits 
     if (txt.find("^[0-9]+$"))
    {
        info("string contains only numbers");
    }

}