Bound methods as blocks in Ruby

gistfile1.txt

class WhiteList 
  def initialize(names)
    @names = names
  end

  def whitelisted?(name)
    @names.include? name
  end
end

w = WhiteList.new %w(Alice Bob)
%w(Alice Bob John Mark James).select &w.method(:whitelisted?) => ['Alice', 'Bob']