# File lib/mongo/collection.rb, line 879
    def distinct(key, query=nil, opts={})
      raise MongoArgumentError unless [String, Symbol].include?(key.class)
      command            = BSON::OrderedHash.new
      command[:distinct] = @name
      command[:key]      = key.to_s
      command[:query]    = query

      @db.command(command, command_options(opts))["values"]
    end