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: multi_tenant.rb
    path of file: ./repos/activerecord-multi-tenant/lib/activerecord-multi-tenant
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

require 'active_support/current_attribute
    
  def self.without(&block)
    return block.call if current_tenant.nil?

    old_tenant = current_tenant
    begin
      self.current_tenant = nil
      block.call
    ensure
      self.current_tenant = old_tenant
    end