docs: def fas_group_member_filter(config, message, group=None, *args, **kw):
      """ Messages regarding any member of a FAS group
  
      Use this rule to include messages that have anything to do with **any
      user** belonging to a particular fas group.  You might want to use this
      to monitor the activity of a group for which you are responsible.
      """
      if not group:
          return False
      fasusers = _get_users_of_group(config, group)
      msgusers = fmn.rules.utils.msg2usernames(message, **config)
      return bool(fasusers.intersection(msgusers))