@pimms.value<EOL><INDENT>def indexed_neighborhoods(vertex_index, neighborhoods):<DEDENT>
return tuple([tuple([vertex_index[u] for u in nei]) for nei in neighborhoods])<EOL>
tess.indexed_neighborhoods is a tuple whose contents are the neighborhood of each vertex in
the given tesselation; this is identical to tess.neighborhoods except this gives the vertex
indices where tess.neighborhoods gives the vertex labels.