Question on why eigenvectors with eignelvalues of zero are not filtered out in code

[sidhantls]

The paper mentions that the first k non-zero eigenvalues of the laplacian are used for Phi(k). However, in the code, I don't see filtering the zero-eigenvalues out by setting a low threshold of 1e-6 for example. Phi(1) contains the lowest non-zero eigenvalue and Phi(k) contains the lowest K non-zero eigenvalues, right, according to the Figure 1? Here

In that case, why aren't the eigenvalues with low mangitude, eigenvalue < e-6, filtered out in get_k_lowest_eig? Here. To get the lowest k non-zero eigenvalues. If the eigenvalue is less than 1e-6 they could be considered as the zero eigenvalues and hence filtered out?

Would be great if you could share your thoughts on this