code: def _extract_keys(d):
      """ """
      keys = []
  
      for key, value in d.items():
          if isinstance(value, Mapping):
              keys.extend([key] + tail for tail in _extract_keys(value))
          else:
              keys.append([key])
  
      return keys
  
imports: from collections.abc import Mapping
  from uuid import uuid4
  import sqlite3
  import json
  import importlib
  import pandas
  from jinja2 import Template
  from sklearn_evaluation.table import Table
  from sklearn_evaluation.report.serialize import try_serialize_figures, figure2html
  from sklearn_evaluation.telemetry import SKLearnEvaluationLogger
  from sklearn_evaluation.nb.NotebookCollection import add_compare_tab, tabs_html_from_content, HTMLMapping
  from sklearn_evaluation import plot
label_desc: Use image node_id 10 for calling a global function with example usage: _extract_keys(d) and returns: keys