code: def __init__(self):
      self.colnames = set()
      self.refnames = set()
  
imports: import ast
  import datetime
  from typing import Any, Dict
  import numpy
  from numba import cuda
  import cudf
  from cudf.core.buffer import acquire_spill_lock
  from cudf.core.column import column_empty
  from cudf.utils import applyutils
  from cudf.utils._numba import _CUDFNumbaConfig
  from cudf.utils.dtypes import BOOL_TYPES, DATETIME_TYPES, NUMERIC_TYPES, TIMEDELTA_TYPES
label_desc: Use image node_id 1 to create a new _NameExtractor object from inherited base classes: ast with example: obj = _NameExtractor()