code: def _init_generator(seed: Optional[int] = None):
      if seed:
          generator = torch.Generator()
          generator.manual_seed(seed)
          return generator
  
      return None
  
imports: import unittest
  from typing import Optional
  import torch
  import torch.nn
  from opacus import PrivacyEngine
  from opacus.data_loader import DPDataLoader, switch_generator
  from opacus.grad_sample import GradSampleModule
  from opacus.optimizers import DPOptimizer
  from torch.utils.data import DataLoader, TensorDataset
label_desc: Use image node_id 3 for calling a global function with example usage: _init_generator(seed) and returns: None, generator