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: unicode_username_allowlist_validator.rb
    path of file: ./repos/discourse/lib/validators
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

class UnicodeUsernameAllowlistValidator
  def initialize(opts = {})
    @opts = opts
  end

  def valid_value?(value)
    @error_message = nil
    return true if value.blank?

    if value.match?(%r{\A/.*/
    
  def valid_value?(value)
    @error_message = nil
    return true if value.blank?

    if value.match?(%r{\A/.*/[imxo]*\z})
      @error_message =
        I18n.t("site_settings.errors.allowed_unicode_usernames.leading_trailing_slash")
    else
      begin
        Regexp.new(value)
      rescue RegexpError => e
        @error_message =
          I18n.t("site_settings.errors.allowed_unicode_usernames.regex_invalid", error: e.message)
      end