class method self.deprecated_associations_options=

# File activerecord/lib/active_record.rb, line 479
  def self.deprecated_associations_options=(options)
    raise ArgumentError, "deprecated_associations_options must be a hash" unless options.is_a?(Hash)

    valid_keys = [:mode, :backtrace]

    invalid_keys = options.keys - valid_keys
    unless invalid_keys.empty?
      inflected_key = invalid_keys.size == 1 ? "key" : "keys"
      raise ArgumentError, "invalid deprecated_associations_options #{inflected_key} #{invalid_keys.map(&:inspect).to_sentence} (valid keys are #{valid_keys.map(&:inspect).to_sentence})"
    end

    options.each do |key, value|
      ActiveRecord::Associations::Deprecation.send("#{key}=", value)
    end
  end