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: config.rb
    path of file: ./repos/cancancan/lib/cancan
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module CanCan
  def self.valid_accessible_by_strategies
    strategies = [:left_join]

    unless does_not_support_subquery_strategy?
      strategies.push(:joined_alias_exists_subquery, :joined_alias_each_rule_as_exis
    
  def self.accessible_by_strategy=(value)
    validate_accessible_by_strategy!(value)

    if value == :subquery && does_not_support_subquery_strategy?
      raise ArgumentError, 'accessible_by_strategy = :subquery requires ActiveRecord 5 or newer'
    end

    @accessible_by_strategy = value
  end