how does "findcontours" store contours?

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Hi, I use the function cv::findcontours(InputOutputArray image, OutputArrayOfArrays contours, OutputArray hierarchy, int mode, int method, Point offset=Point()) for detecting circular contours in an image. I want to know the sequence of contours it stores in the variable contours. From my test, it seems the function detects the contours from the bottom right to the top left of the image. Is that right?