"rv_to_tle" function in satellite toolbox

I am using SGP4 package in satellite toolbox. But I want to modify bstar term at every orbit. For this purpose, I am trying to propagate a given tle for a single orbit and define a new tle at that point. Then I want to propagate the new tle for the next orbit and create another tle after that. but I am having problem with rv_to_tle function; it requires a matrix W which defines weights for least square algorithm. I cant define this matrix. Can somebody help me? (It says W = I but I dont know how to define ‘I’)
I am using python in jupyter lab and using julia through a julia interpreter called “pyjulia”

Isn’t this usual notation for the identity matrix?

using LinearAlgebra



Thanks! It is.