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: project.rb
    path of file: ./repos/transpec/tasks/lib
    
    the code of the file until where you have to start completion: # coding: utf-8

require 'transpec'
require 'fileutils'

class Project
  include FileUtils # This is Rake's one.

  BUNDLER_RETRY_COUNT = 3

  attr_reader :url, :ref, :bundler_args

  def self.base_dir
    @base_dir ||= begin
      path = ba
    
  def with_clean_bundler_env
    if defined?(Bundler)
      Bundler.with_clean_env do
        # Bundler.with_clean_env cleans environment variables
        # which are set after bundler is loaded.
        prepare_env
        yield
      end
    else
      prepare_env
      yield
    end