code: func (g *Graph) Remove(v Vertex) Vertex {
  	// Delete the vertex itself
  	g.vertices.Delete(v)
  	g.debug.Remove(v)
  
  	// Delete the edges to non-existent things
  	for _, target := range g.DownEdges(v).List() {
  		g.RemoveEdge(BasicEdge(v, target))
  	}
  	for _, source := range g.UpEdges(v).List() {
  		g.RemoveEdge(BasicEdge(source, v))
  	}
  
  	return nil
  }
docs: // Remove removes a vertex from the graph. This will also remove any
  // edges with this vertex as a source or target.