You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: observations.rb
    path of file: ./repos/mushroom-observer/app/classes/report/darwin
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module Report
  module Darwin
    # Darwin Core Observations format.
    class Observations < Report::CSV
      attr_accessor :ids, :taxon_set

      def self.separator
   
    
      def labels
        %w[
          CatalogNumber
          OccurrenceID
          BasisOfRecord
          DateLastModified
          InstitutionCode
          CollectionCode
          ScientificName
          ScientificNameAuthor
          ScientificNameRank
          Genus
          Species
          Subspecies
          Collector
          DateCollected
          YearCollected
          MonthCollected
          DayCollected
          Country
          StateProvince
          County
          Locality
          Latitude
          Longitude
          MinimumElevation
          MaximumElevation
          Notes
        ].freeze
      end