code: def record_identity(record)
        identity = record.try(:[], :id) || record.try(:[], "id") || record.try(:id)
        raise "Cannot obtain identity of the #{record}" if identity.blank?
        {
          :id => identity
        }
      end
docs: Returns a hash with a simple record identity
  
   @param record [ApplicationRecord, Hash] list of stored records
   @return [Hash{Symbol => Bigint}] record identity