code: def save_artifacts(self):
      tracker.save(
          {
              "target.": self.y,
              "ref.": self.reference,
              "strike_low.": self.strike_low,
              "strike_high.": self.strike_high,
          }
      )
  
file_path: labml/samples/stocks/dataset.py
imports: import numpy
  import torch
  from labml import monit, lab
  from labml import tracker
  from torch.utils.data import Dataset
  from stocks import CandleIdx
  from stocks.build_numpy_cache import build_cache
label_desc: Use image node_id 4 for calling the MinutelyDataset obj's underlying member method code with example usage: obj.save_artifacts() without return types