docs: def strongly_connected_components(self):
          """
          Return list of strongly connected components of this graph.
  
          Returns a list of subgraphs.
  
          Algorithm is based on that described in "Path-based depth-first search
          for strong and biconnected components" by Harold N. Gabow,
          Inf.Process.Lett. 74 (2000) 107--114.
  
          """
          raw_sccs = self._component_graph()
  
          sccs = []
          for raw_scc in raw_sccs:
              sccs.append([v for vtype, v in raw_scc if vtype == 'VERTEX'])
  
          return [self.full_subgraph(scc) for scc in sccs]