class_docstr: Use mlflow to implement Experiment.
class_docstr_tok: ["Use","mlflow","to","implement","Experiment","."]
code: def start(
      self, *, recorder_id=None, recorder_name=None, resume=False
  ):
      logger.info(f"Experiment {self.id} starts running ...")
      # Get or create recorder
      if recorder_name is None:
          recorder_name = self._default_rec_name
      # resume the recorder
      if resume:
          recorder, _ = self._get_or_create_rec(
              recorder_id=recorder_id, recorder_name=recorder_name
          )
      # create a new recorder
      else:
          recorder = self.create_recorder(recorder_name)
      # Set up active recorder
      self.active_recorder = recorder
      # Start the recorder
      self.active_recorder.start_run()
  
      return self.active_recorder
  
imports: from typing import Dict, List, Union
  from qlib.typehint import Literal
  import mlflow
  from mlflow.entities import ViewType
  from mlflow.exceptions import MlflowException
  from .recorder import Recorder, MLflowRecorder
  from ..log import get_module_logger
label_desc: Use image node_id 3 for calling the MLflowExperiment obj's underlying member method code with example usage: obj.start() and returns: self