You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: graph_filter.rb
    path of file: ./repos/aws-security-viz/lib
    
    the code of the file until where you have to start completion: require 'rgl/traversal'
require 'rgl/implicit'

class GraphFilter
  def initialize(graph)
    @graph = graph
  end

  def filter(source, destination)
    return @graph if source.nil? && destination.nil?
    if !source.nil? && destinati
    
  def search(graph, source, destination)
    visitor = RGL::DFSVisitor.new(graph)
    path = []
    paths = []
    visitor.set_examine_vertex_event_handler { |x| path << x }
    visitor.set_finish_vertex_event_handler { |x| path.pop }
    visitor.set_examine_edge_event_handler { |x, y| paths << path.clone + [y] if y == destination }
    graph.depth_first_visit(source, visitor) { |x|}
    to_remove = graph.vertices - paths.flatten
    graph.remove_vertices(*to_remove)
    graph
  end