code: def _data_target(self, s):
      s = s.replace("?", '"nan"')
  
      values = json.loads(f"[{s}]")
      assert values, (
          "A given series should contains a set of comma separated numeric"
          " values. At least one numeric value should be there in a series."
          " Missing values should be indicated with ? symbol"
      )
  
      return np.array(values, dtype=float)
  
imports: from datetime import datetime
  from distutils.util import strtobool
  from types import SimpleNamespace
  from typing import Dict
  import numpy
  from toolz import compose_left
  from gluonts import json
  from gluonts.exceptions import GluonTSDataError
label_desc: Use image node_id 5 for calling the TSFReader obj's underlying member method code with example usage: obj._data_target(s) and returns: np