how to get the value of principal curvatures?

[keblicuey]

Issue #143 has mentioned this question. However, I can't find the vertex_quality_array function in Mesh class. And I just found the function vertex_curvature_principal_dir1_matrix(self: pmeshlab.Mesh) and vertex_curvature_principal_dir2_matrix(self: pmeshlab.Mesh) to caculate the principal curvature directions. So how can I get the value of principal curvatures or guassian curvature and mean curvature other than visulize them with ply mesh data.

[keblicuey]

#352 also mentioned the confusion.