code: def fetch_build_egg(self, req):
  		
  		from setuptools.command.easy_install import easy_install
  		dist = Distribution({'script_args': ['easy_install']})
  		dist.parse_config_files()
  		opts = dist.get_option_dict('easy_install')
  		keep = (
  			'find_links', 'site_dirs', 'index_url', 'optimize',
  			'site_dirs', 'allow_hosts'
  		)
  		for key in list(opts):
  			if key not in keep:
  				del opts[key]  # don't use any other settings
  		if self.dependency_links:
  			links = self.dependency_links[:]
  			if 'find_links' in opts:
  				links = opts['find_links'][1].split() + links
  			opts['find_links'] = ('setup', links)
  		if self.allow_hosts:
  			opts['allow_hosts'] = ('test', self.allow_hosts)
  		if self.index_url:
  			opts['index_url'] = ('test', self.index_url)
  		install_dir_func = getattr(self, 'get_egg_cache_dir', _os.getcwd)
  		install_dir = install_dir_func()
  		cmd = easy_install(
  			dist, args=["x"], install_dir=install_dir,
  			exclude_scripts=True,
  			always_copy=False, build_directory=None, editable=False,
  			upgrade=False, multi_version=True, no_report=True, user=False
  		)
  		cmd.ensure_finalized()
  		return cmd.easy_install(req)
docs: Specialized version of Distribution.fetch_build_egg
  		that respects respects allow_hosts and index_url.