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: single_recipient_validator.rb
    path of file: ./repos/gitlabhq/lib/gitlab/email
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module Gitlab
  modu
    
      def validate_single_recipient_in_opts!(opts)
        return unless opts

        symbolized_opts = opts.symbolize_keys

        if opts.keys.length != symbolized_opts.keys.length
          raise Gitlab::Email::MultipleRecipientsError, "opts has colliding key names"
        end