Permute function rearranges the dimensions of an array(t2m) in the order specified by the vector i.e [2,1,3] in your case.
If t2m is a N-dimensional array, the vector should contain N elements.
The reason behind the error is that
t2m is not a 3 Dimensional array, so your vector [2,1,3] of length 3 should be modified based of the dimensions of t2m.
Hope this helps!