code: def show_avaliable_metrics() -> Dict:
      """
      Get the dict of current avaliable metrics.
  
      Returns:
          (`Dict`)
              A Dict which key is the class name of metrics implementation(e.g. TMMetrics),
              and the value is a dict has keys 'impl' and 'names'. 'impl' is the framework
              to implement this metric class and 'names' is the list of names of metrics
              which can be created to calculate the metric.
  
      Example:
          >>> from towhee.trainer.metrics import show_avaliable_metrics
          >>> aval_metrics = show_avaliable_metrics()
          >>> 'TMMetrics' in aval_metrics
          True
      """
      global _metrics_meta
      return _metrics_meta
  
imports: from typing import Any, Dict
  import torchmetrics
  from torchmetrics.detection.map import MeanAveragePrecision
label_desc: Use image node_id 2 for calling a global function with example usage: show_avaliable_metrics() and returns: _metrics_meta