python3-toposort 1.6-1 (amd64 binary) in ubuntu hirsute

 In computer science, a topological sort (sometimes abbreviated
 topsort or toposort) or topological ordering of a directed graph is a
 linear ordering of its vertices such that for every directed edge uv
 from vertex u to vertex v, u comes before v in the ordering.
 .
 This package provides this algorithm for Python 3.