docs: def get_seeds(self, threshold):
          """ Returns a list of seed points for isosurface extraction
              given a threshold value
              @ In, threshold, float, the isovalue for which we want to
                  identify seed points for isosurface extraction
          """
          seeds = []
          for e1, e2 in self.superArcs:
              # Because we did some extra work in _process_tree, we can
              # safely assume e1 is lower than e2
              if self.Y[e1] <= threshold <= self.Y[e2]:
                  if (e1, e2) in self.augmentedEdges:
                      # These should be sorted
                      edgeList = self.augmentedEdges[(e1, e2)]
                  elif (e2, e1) in self.augmentedEdges:
                      e1, e2 = e2, e1
                      # These should be reverse sorted
                      edgeList = list(reversed(self.augmentedEdges[(e1, e2)]))
                  else:
                      continue
  
                  startNode = e1
                  for endNode in edgeList + [e2]:
                      if self.Y[endNode] >= threshold:
                          # Stop when you find the first point above the
                          # threshold
                          break
                      startNode = endNode
  
                  seeds.append(startNode)
                  seeds.append(endNode)
          return seeds