Noise Covariance Matrix

[Aseman7]

Can I modify the SpectrumModel() function to include the noise covariance matrix (a_N)? How can I go about doing that? When would it be beneficial to add it?

I found that I can use it as a prior, for example, in the form of:
"a_n": st.norm(1, 0.25)

If you could elaborate on it, I would be extremely appreciative.