code: def start(self):
      if not migrate():
          self.log.info("Found nothing to migrate.")
  
file_path: catboost/contrib/python/jupyter-core/py2/jupyter_core/migrate.py
imports: from __future__ import unicode_literals
  import os
  import re
  import shutil
  from datetime import datetime
  from traitlets.config import PyFileConfigLoader, JSONFileConfigLoader
  from traitlets.log import get_logger
  from .utils import ensure_dir_exists
  from .paths import jupyter_config_dir, jupyter_data_dir
  from .application import JupyterApp
label_desc: Use image node_id 1 for calling the JupyterMigrate obj's underlying member method code with example usage: obj.start() without return types