code: def __enter__(self):
      if self._session_depth == 0:
          assert self._session is None
          self._session = self.get_session(autocommit=False)
      self._session_depth += 1
      return self
  
imports: from aim.storage.structured.entities import ObjectFactory, Run, Experiment, Tag, RunCollection, ExperimentCollection, TagCollection
  from aim.storage.structured.sql_engine.entities import ModelMappedRun, ModelMappedExperiment, ModelMappedTag
  from typing import List
  from datetime import datetime
label_desc: Use image node_id 21 for calling the ModelMappedFactory obj's underlying member method code with example usage: obj.__enter__() and returns: self