class Redis

def migrate(key, options)
  host = options[:host] || raise(RuntimeError, ":host not specified")
  port = options[:port] || raise(RuntimeError, ":port not specified")
  db = (options[:db] || @client.db).to_i
  timeout = (options[:timeout] || @client.timeout).to_i
  synchronize do |client|
    client.call([:migrate, host, port, key, db, timeout])
  end
end