How to grab matrix value

To grab value of matrix knob, we need use an indexing.
Format :
matrixknob.value(x,y) , where x and y is 2d index.

For example in 3dTransform node, we have 4x4 matrix like this format :

00 - 01 - 02 - 03
10 - 11 - 12 - 13
20 - 21 - 22 - 23
30 - 31 - 32 - 33

so to access element 32 , we use : matrixknob.value(3,2) etc.