How to get the height of the text in a Text Layout?

Hey, I'm using the text layout and I read the documentation and now capable of doing almost all what I need. I just have a small problem. Lets say I have a text layout object on my stage containing some text. How can I know the height of the text or the number of lines in it ???

I found their is a porperty: "contentHeight"  and a method "calculateHeight()" but they are in another class of the libraries that comes with the text layout component. I don't know how to reach them. Please help and write me the lines of code that do this job.

Thanks