code: def add_site_list(dir_list):
      
      
      our_site_packages = os.path.abspath(os.path.join(sys.prefix, site_package_postfix))
      dir_list = [os.path.abspath(x) for x in dir_list]
  
      prepend = SysPathInserter(0)
      append = SysPathInserter()
  
      try:
          our_index = dir_list.index(our_site_packages)
      except ValueError:
          our_index = None
  
      for i, dir_name in enumerate(dir_list):
          if our_index is None or i < our_index:
              add_site_dir(dir_name, _path=prepend)
          else:
              add_site_dir(dir_name, _path=append)
docs: Add a list of pseudo site-packages to :data:`python:sys.path`.
  
      This centers the list on ``sys.path`` around the current environment.
      I.e. if this environment is in the list, then directories before it in the
      list will be prepended to ``sys.path``, and directories after it will
      be appended to ``sys.path``.