docs: def _find_observable_paths(extra_files=None):
      """Finds all paths that should be observed."""
      rv = set(
          os.path.dirname(os.path.abspath(x)) if os.path.isfile(x) else os.path.abspath(x)
          for x in sys.path
      )
  
      for filename in extra_files or ():
          rv.add(os.path.dirname(os.path.abspath(filename)))
  
      for module in list(sys.modules.values()):
          fn = getattr(module, "__file__", None)
          if fn is None:
              continue
          fn = os.path.abspath(fn)
          rv.add(os.path.dirname(fn))
  
      return _find_common_roots(rv)