code: def test_metrics_to_str():
      """Test the string representation of the metrics dictionary."""
      metrics = {"metric1": 0.9134, "metric2": 0.3213}
      expected_metrics_str = "metric1: 0.9134\tmetric2: 0.3213\t"
      metric_str = Model._metrics_to_str(metrics)
      assert expected_metrics_str == metric_str
  
imports: from typing import List
  import numpy
  import pytest
  import torch
  import torch.nn
  import torch.optim
  from torch.utils.data import DataLoader, TensorDataset
  from alibi.models.pytorch.metrics import AccuracyMetric, LossContainer
  from alibi.models.pytorch.model import Model
label_desc: Use image node_id 19 for calling a global function with example usage: test_metrics_to_str() without return types