code: def main(argv, version=DEFAULT_VERSION):
      
      try:
          import setuptools
      except ImportError:
          egg = None
          try:
              egg = download_setuptools(version, delay=0)
              sys.path.insert(0,egg)
              from setuptools.command.easy_install import main
              return main(list(argv)+[egg])   # we're done here
          finally:
              if egg and os.path.exists(egg):
                  os.unlink(egg)
      else:
          if setuptools.__version__ == '0.0.1':
              print >>sys.stderr, (
              "You have an obsolete version of setuptools installed.  Please\n"
              "remove it from your system entirely before rerunning this script."
              )
              sys.exit(2)
  
      req = "setuptools>="+version
      import pkg_resources
      try:
          pkg_resources.require(req)
      except pkg_resources.VersionConflict:
          try:
              from setuptools.command.easy_install import main
          except ImportError:
              from easy_install import main
          main(list(argv)+[download_setuptools(delay=0)])
          sys.exit(0) # try to force an exit
      else:
          if argv:
              from setuptools.command.easy_install import main
              main(argv)
          else:
              print "Setuptools version",version,"or greater has been installed."
              print '(Run "ez_setup.py -U setuptools" to reinstall or upgrade.)'
docs: Install or upgrade setuptools and EasyInstall