code: def objective(x, a, b):
      return a * (x**2) + b
  
file_path: ray/doc/source/tune/doc_code/key_concepts.py
imports: from ray import train
  from ray import tune
  from ray.tune.search.bayesopt import BayesOptSearch
  from ray import train
  from ray.tune.schedulers import HyperBandScheduler
label_desc: Use image node_id 3 for calling a global function with example usage: objective(x, a, b) and returns: unknown