code: def _validate_metadata(self, metadata):
      required_metadata = [
          "author",
          "description",
          "ms.author",
          "ms.topic",
          "title",
      ]
      for req in required_metadata:
          assert (
              req in metadata.keys()
          ), f"{req} is required metadata, please add it to manifest file"
  
imports: import os
  import pathlib
  import re
  import shutil
  import warnings
  from datetime import datetime
  from os.path import basename, dirname
  from typing import List
  from urllib.parse import urlparse
  import markdown
  import pypandoc
  import requests
  from bs4 import BeautifulSoup
  from docgen.core import Channel, ParallelChannel
  from markdownify import ATX, MarkdownConverter
  from nbconvert import MarkdownExporter
  from nbformat import read
  from traitlets.config import Config
label_desc: Use image node_id 7 for calling the FabricChannel obj's underlying member method code with example usage: obj._validate_metadata(metadata) without return types