# File lib/redis/distributed.rb, line 799
    def ensure_same_node(command, keys)
      all = true

      tags = keys.map do |key|
        tag = key_tag(key)
        all = false unless tag
        tag
      end

      if (all && tags.uniq.size != 1) || (!all && keys.uniq.size != 1)
        # Not 1 unique tag or not 1 unique key
        raise CannotDistribute, command
      end

      yield(node_for(keys.first))
    end