class RSpec::Core::SharedExampleGroup::Registry

def add(context, name, *metadata_args, &block)
  ensure_block_has_source_location(block) { CallerFilter.first_non_rspec_line }
  if valid_name?(name)
    warn_if_key_taken context, name, block
    shared_example_groups[context][name] = block
  else
    metadata_args.unshift name
  end
  unless metadata_args.empty?
    mod = Module.new
    (class << mod; self; end).__send__(:define_method, :included) do |host|
      host.class_exec(&block)
    end
    RSpec.configuration.include mod, *metadata_args
  end
end