class Redis::Cluster::Node

def try_map
  errors = {}
  results = {}
  @clients.each do |node_key, client|
    begin
      reply = yield(node_key, client)
      results[node_key] = reply unless reply.nil?
    rescue CommandError => err
      errors[node_key] = err
      next
    end
  end
  return results if errors.empty?
  raise CommandErrorCollection, errors
end