load_yaml

# File lib/rubygems.rb, line 645
  def self.load_yaml
    begin
      gem 'psych', '~> 1.2', '>= 1.2.1' unless ENV['TEST_SYCK']
    rescue Gem::LoadError
      # It's OK if the user does not have the psych gem installed.  We will
      # attempt to require the stdlib version
    end

    begin
      # Try requiring the gem version *or* stdlib version of psych.
      require 'psych' unless ENV['TEST_SYCK']
    rescue ::LoadError
    ensure
      require 'yaml'
    end

    # Hack to handle syck's DefaultKey bug with psych.
    # See the note at the top of lib/rubygems/requirement.rb for
    # why we end up defining DefaultKey more than once.
    if !defined? YAML::Syck
      YAML.module_eval do
          const_set 'Syck', Module.new {
            const_set 'DefaultKey', Class.new
          }
        end
    end
  end