docstr: Saves model when validation loss decreases.
docstr_tok: ["Saves","model","when","validation","loss","decreases","."]
code: def save_checkpoint(self, model):
      """Saves model when validation loss decreases."""
      self.model = pickle.dumps(model.state_dict())
  
file_path: AutoGL/test/performance/heterogeneous/dgl/helper.py
imports: import numpy
  import pickle
label_desc: Use image node_id 3 for calling the EarlyStopping obj's underlying member method code with example usage: obj.save_checkpoint(model) without return types