concat_records

# File activerecord/lib/active_record/associations/collection_association.rb, line 516
        def concat_records(records, should_raise = false)
          result = true

          records.flatten.each do |record|
            raise_on_type_mismatch!(record)
            add_to_target(record) do |rec|
              result &&= insert_record(rec, true, should_raise) unless owner.new_record?
            end
          end

          result && records
        end