code: def scheduler_example(optimizer):
      if cfg.optim.optimizer == "reduce":
          scheduler = optim.lr_scheduler.ReduceLROnPlateau(optimizer)
          return scheduler
  
imports: import torch.optim
  from graphgym.config import cfg
  from graphgym.register import register_optimizer, register_scheduler
label_desc: Use image node_id 2 for calling a global function with example usage: scheduler_example(optimizer) and returns: scheduler