# File lib/rds/right_rds_interface.rb, line 156
    def describe_db_instances(params={}, &block)
      item, params = AwsUtils::split_items_and_params(params)
      params = params.dup
      params['DBInstanceIdentifier'] = item if item
      result = []
      incrementally_list_items('DescribeDBInstances', DescribeDbInstancesParser, params) do |response|
        result += response[:db_instances]
        block ? block.call(response) : true
      end
      result
    end