root path question

[matianhe3]

    file = readxml("f0dc19ff.xml")
    nums = findall("//TT", file)
    for num in nums
        counter = findall("//contour", num))
        println(length(counter))

<TT><contour></contour></TT>
<TT><contour></contour></TT>
<TT><contour></contour></TT>
<TT><contour></contour></TT>
<TT><contour></contour></TT>
<TT><contour></contour></TT>

i think it will print 1 , i want get every => num.
but it gives me 6, findall seems not in num , it still search in file?
i must use counter = findall("//contour", parsexml(string(num))) get the result that i need.