docs: def _find_files(dirpath: str) -> 'Iterable[str]':
      """Find files recursively.
  
      Returns a generator that yields paths in no particular order.
      """
      for dirpath, dirnames, filenames in os.walk(dirpath, topdown=True,
                                                  followlinks=True):
          if os.path.basename(dirpath).startswith('.'):
              del dirnames[:]
          for filename in filenames:
              yield os.path.join(dirpath, filename)