code: def _pattern(*names, **kwargs):
      
      if 'extension' not in kwargs:
          kwargs['extension'] = '--*'
      return os.path.join(*names) + kwargs['extension']
docs: Returns globbing pattern for name1/name2/../lastname + '--*' or
      name1/name2/../lastname + extension if parameter `extension` it set.
  
      Parameters
      ----------
      names : strings
          Which path to join. Example: _pattern('path', 'to', 'experiment') will
          return `path/to/experiment--*`.
      extension : string
          If other extension then --* is wanted.
          Example: _pattern('path', 'to', 'image', extension='*.png') will return
          `path/to/image*.png`.
  
      Returns
      -------
      string
          Joined glob pattern string.