code: def non_empty(self) -> bool:
      return self._idx >= 0
  
imports: from hail import ir
  import abc
  from typing import Sequence, MutableSequence, List, Set, Dict, Optional
  from collections import namedtuple
label_desc: Use image node_id 5 for calling the RQStack obj's underlying member method code with example usage: obj.non_empty() and returns: unknown