class Bundler::Molinillo::DependencyGraph::DetachVertexNamed

def down(graph)
  return unless @vertex
  graph.vertices[@vertex.name] = @vertex
  @vertex.outgoing_edges.each do |e|
    e.destination.incoming_edges << e
  end
  @vertex.incoming_edges.each do |e|
    e.origin.outgoing_edges << e
  end
end