docs: def expand_path(path, follow_links=False):
      """ Expand shell variables ("$VAR"), user directory symbols (~), and return absolute path
  
      >>> path0 = '~/whatever.txt'
      >>> path = expand_path(path0)
      >>> path.endswith(path0[2:])
      True
      >>> len(path) > len(path0)
      True
      >>> '~' in path
      False
      >>> path.startswith(os.path.sep)
      True
      """ 
      path = os.path.expandvars(os.path.expanduser(path))
      if follow_links:
          return os.path.realpath(path)
      return os.path.abspath(path)