<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _get_all_run_infos(self):
 """Find the RunInfos for all runs since the last clean-all."""

    info_dir = self._settings.info_dir
    if not os.path.isdir(info_dir):
      return []
    paths = [os.path.join(info_dir, x) for x in os.listdir(info_dir)]

    # We copy the RunInfo as a dict, so we can add stuff to it to pass to the template.
    # We filter only those that have a timestamp, to avoid a race condition with writing
    # that field.
    return [d for d in
            [RunInfo(os.path.join(p, 'info')).get_as_dict() for p in paths
             if os.path.isdir(p) and not os.path.islink(p)]
            if 'timestamp' in d]