class Redis::Distributed

def exists(*args)

Determine if a key exists. 
def exists(*args)
  if !Redis.exists_returns_integer && args.size == 1
    ::Redis.deprecate!(
      "`Redis#exists(key)` will return an Integer in redis-rb 4.3, if you want to keep the old behavior, " \
      "use `exists?` instead. To opt-in to the new behavior now you can set Redis.exists_returns_integer = true. " \
      "(#{::Kernel.caller(1, 1).first})\n"
    )
    exists?(*args)
  else
    keys_per_node = args.group_by { |key| node_for(key) }
    keys_per_node.inject(0) do |sum, (node, keys)|
      sum + node._exists(*keys)
    end
  end
end