code: def flatten_metric_names(metric_names):
      def to_list(names):
          return names if isinstance(names, (tuple, list)) else [names]
  
      return [name for names in metric_names for name in to_list(names)]
  
file_path: poutyne/poutyne/framework/metrics/utils.py
imports: import re
  from collections import Counter
  from typing import List, Tuple
label_desc: Use image node_id 3 for calling a global function with example usage: flatten_metric_names(metric_names) and returns: unknown, unknown