docs: def _find_project_config_file(user_config_file):
      """Find path to project-wide config file
      Search from current working directory, and traverse path up to
      directory with .versionner.rc file or root directory
  
      :param user_config_file: instance with user-wide config path
      :type: pathlib.Path
      :rtype: pathlib.Path
      """
      proj_cfg_dir = pathlib.Path('.').absolute()
      proj_cfg_file = None
      root = pathlib.Path('/')
      while proj_cfg_dir != root:
          proj_cfg_file = proj_cfg_dir / defaults.RC_FILENAME
          if proj_cfg_file.exists():
              break
  
          proj_cfg_file = None
          # pylint: disable=redefined-variable-type
          proj_cfg_dir = proj_cfg_dir.parent
  
      if proj_cfg_file and proj_cfg_file != user_config_file:
          return proj_cfg_file