code: def _create_study(resume, create_kwargs, backend):
      if not resume:
          load_if_exists = False
          print("Starting a new tuning")
      else:
          load_if_exists = True
          print("Resume the last tuning...")
      create_kwargs["load_if_exists"] = load_if_exists
      # create study
      return backend.create_study(**create_kwargs)
  
file_path: BigDL/python/nano/src/bigdl/nano/automl/hpo/search.py
imports: import optuna
  from bigdl.nano.utils.common import invalidInputError
label_desc: Use image node_id 4 for calling a global function with example usage: _create_study(resume, create_kwargs, backend) and returns: backend