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: base.rb
    path of file: ./repos/sequencescape/app/models/accessionable
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
# Base class to control generating XML for accessioning with the ENA or EGA
# @see AccessionService
class Accessionable::Base
  InvalidData = Class.new(AccessionService::AccessionServiceError)
  attr_reader :accession_number, :name, :date, :date_short

  def initialize(accession_number)
    @accession_number = accession_number

    time_now = Time.zone.now
    @date = time_now.strftime('%Y-%m-%dT%H:%M:%SZ')
    @date_short = time_now.strftime('%Y-%m-%d')
  end

  def errors
    []
  end

  def xml
    raise NotImplementedError, 'abstract method'
  end

  def center_name
    AccessionService::CenterName
  end

  def schema_type
    # raise NotImplementedError, "abstract method"
    self.class.name.split('::').last.downcase
  end

  def alias
    "#{name.gsub(/[^a-z\d]/i, '_')}-sc-#{accessionable_id}"
  end

  def file_name
    "#{self.alias}-#{date}.#{schema_type}.xml"
  end

  def extract_accession_number(xmldoc)
    element = xmldoc.root.elements["/RECEIPT/#{schema_type.upcase}"]
    accession_number = element && element.attributes['accession']
  end

  def extract_array_express_accession_number(xmldoc)
    element = xmldoc.root.elements["/RECEIPT/#{schema_type.upcase}/EXT_ID[@type='ArrayExpress']"]
    accession_number = element && element.attributes['accession']
  end

  def update_accession_number!(_user, _accession_number)
    raise NotImplementedError, 'abstract method'
  end

  def update_array_express_accession_number!(accession_number); end

  def accessionable_id
    raise NotImplementError, 'abstract method'
  end

  def released?
    # Return false by default. Overidden by sample.
    false
  end

  def add_updated_event(user, classname, eventable)
    eventable.events.create(
      created_by: user.login,
      message: "#{classname} #{eventable.id} accession data has been updated by user #{user.login}",
      content: 'accessi
    
  def update_array_express_accession_number!(accession_number); end

  def accessionable_id
    raise NotImplementError, 'abstract method'
  end

  def released?
    # Return false by default. Overidden by sample.
    false
  end

  def add_updated_event(user, classname, eventable)
    eventable.events.create(
      created_by: user.login,
      message: "#{classname} #{eventable.id} accession data has been updated by user #{user.login}",
      content: 'accession number regenerated',
      of_interest_to: 'administrators'
    )
  end

  def label_scope
    @label_scope ||= "metadata.#{self.class.name.split('::').last.downcase}.metadata"
  end

  class Tag
    attr_reader :value

    # Value serialization for accessioning XML generation
    # It will return the same value without any changes and it applies
    # to all tags
    class FieldSerializer
      NOT_COLLECTED = 'not collected'
      NOT_PROVIDED = 'not provided'
      RESTRICTED_ACCESS = 'restricted access'
      NOT_APPLICABLE_CONTROL_SAMPLE = 'not applicable: control sample'
      NOT_APPLICABLE_SAMPLE_GROUP = 'not applicable: sample group'
      MISSING_SYNTHETIC_CONSTRUCT = 'missing: synthetic construct'
      MISSING_LAB_STOCK = 'missing: lab stock'
      MISING_THIRD_PARTY_DATA = 'missing: third party data'
      MISSING_DATA_AGGREEMENT_PRE2023 = 'missing: data agreement established pre-2023'
      MISSING_ENDANGERED_SPECIES = 'missing: endangered species'
      MISSING_HUMAN_IDENTIFIABLE = 'missing: human-identifiable'

      OTHER_DEFAULT_SETTINGS = [
        NOT_COLLECTED,
        NOT_PROVIDED,
        RESTRICTED_ACCESS,
        NOT_APPLICABLE_CONTROL_SAMPLE,
        NOT_APPLICABLE_SAMPLE_GROUP,
        MISSING_SYNTHETIC_CONSTRUCT,
        MISSING_LAB_STOCK,
        MISING_THIRD_PARTY_DATA,
        MISSING_DATA_AGGREEMENT_PRE2023,
        MISSING_ENDANGERED_SPECIES,
        MISSING_HUMAN_IDENTIFIABLE
      ].freeze

      def value_for(value)
        value
      end
      def applies_to?(_name)
        true
      end
      def incorrect_format_value
        NOT_PROVIDED
      end
    end