docstr: Return the metrics that should be displayed in the tracking table.
code: def get_grid_metrics(self):
      """Return the metrics that should be displayed in the tracking table."""
      return [
          tt.group(
              "train",
              [
                  tt.leaf("epoch"),
                  tt.leaf("duration", ".1f"),  # duration in minutes
                  tt.leaf("ping"),
                  tt.leaf("ce", ".4f"),  # cross entropy
                  tt.leaf("ppl", ".3f"),  # perplexity
              ],
              align=">",
          ),
          tt.group(
              "valid",
              [
                  tt.leaf("ce", ".4f"),
                  tt.leaf("ppl", ".3f"),
                  tt.leaf("best_ppl", ".3f"),
              ],
              align=">",
          ),
      ]
  
file_path: audiocraft/audiocraft/grids/musicgen/_explorers.py
imports: import typing
  import treetable
  from .._base_explorers import BaseExplorer
label_desc: Use image node_id 2 for calling the LMExplorer obj's underlying member method code with example usage: obj.get_grid_metrics() and returns: list