module RSpec::Core::SharedExampleGroup

def shared_examples(*args, &block)
  if [String, Symbol, Module].any? {|cls| cls === args.first }
    object = args.shift
    ensure_shared_example_group_name_not_taken(object)
    RSpec.world.shared_example_groups[object] = block
  end
  unless args.empty?
    mod = Module.new
    (class << mod; self; end).send(:define_method, :extended) do |host|
      host.class_eval(&block)
    end
    RSpec.configuration.extend(mod, *args)
  end
end