class Redis

def zunionstore(destination, keys, options = {})

Add multiple sorted sets and store the resulting sorted set in a new key. 
def zunionstore(destination, keys, options = {})
  command = CommandOptions.new(options) do |c|
    c.splat :weights
    c.value :aggregate
  end
  synchronize do
    @client.call(:zunionstore, destination, keys.size, *(keys + command.to_a))
  end
end