code: def get_headings(content, underline="-"):
      heading_re = re.compile(
          r"(\w+)(\([^)]*\))?\n\{}+\n".format(underline)
      )
      return {h[0] for h in heading_re.findall(content)}
  
file_path: datasette/tests/test_docs.py
imports: from datasette import app, utils
  from datasette.app import Datasette
  from datasette.filters import Filters
  from pathlib import Path
  import pytest
  import re
label_desc: Use image node_id 1 for calling a global function with example usage: get_headings(content, underline) and returns: unknown