code: def __call__(self, properties):
      properties.enabled = True
      properties.opt_level = "O2"
      properties.cast_model_type = torch.float16
      properties.patch_torch_functions = False
      properties.keep_batchnorm_fp32 = True
      properties.master_weights = True
      properties.loss_scale = "dynamic"
      # properties.fused_optimizer = False
      # properties.enable_ddp_interop = False
      return properties
  
imports: from collections import OrderedDict
  import torch
  from ._initialize import _initialize
  from ._amp_state import _amp_state, warn_or_err, maybe_print
label_desc: Use image node_id 1 for calling the O2 obj's underlying member method code with example usage: obj.__call__(properties) and returns: properties