code: def get_model_select_metric(self, metrics) -> float:
      return metrics.perplexity_per_word
  
imports: import json
  import math
  import operator
  import time
  import torch
  import torch.nn.functional
  from pytext.common.constants import Stage
  from pytext.config.module_config import PerplexityType
  from pytext.data import CommonMetadata
  from pytext.metrics.language_model_metrics import compute_language_model_metric, LanguageModelMetric
  from pytext.utils import cuda
  from .channel import ConsoleChannel, FileChannel
  from .metric_reporter import MetricReporter
label_desc: Use image node_id 7 for calling the LanguageModelMetricReporter obj's underlying member method code with example usage: obj.get_model_select_metric(metrics) and returns: metrics