code: def _get_refs(expr: Expression, builder: Dict[str, Indices]) -> None:
      from hail.ir import GetField, TopLevelReference
  
      for ir in expr._ir.search(
          lambda a: (
              isinstance(a, GetField)
              and not a.name.startswith("__uid")
              and isinstance(a.o, TopLevelReference)
          )
      ):
          src = expr._indices.source
          builder[ir.name] = src._indices_from_ref[ir.o.name]
  
file_path: hail/hail/python/hail/expr/expressions/expression_utils.py
imports: from typing import Set, Dict
  from hail.typecheck import typecheck, setof
  from .indices import Indices, Aggregation
  from ..expressions import Expression, ExpressionException, expr_any
  from ...ir import MakeTuple
label_desc: Use image node_id 5 for calling a global function with example usage: _get_refs(expr, builder) without return types