find_record_by_id

# File activerecord/lib/active_record/nested_attributes.rb, line 626
      def find_record_by_id(klass, records, id)
        if klass.composite_primary_key?
          id = Array(id).map(&:to_s)
          records.find { |record| Array(record.id).map(&:to_s) == id }
        else
          records.find { |record| record.id.to_s == id.to_s }
        end
      end