docs: def custodian_archive(packages=None):
      """Create a lambda code archive for running custodian.
  
      Lambda archive currently always includes `c7n` and
      `pkg_resources`. Add additional packages in the mode block.
  
      Example policy that includes additional packages
  
      .. code-block:: yaml
  
          policy:
            name: lambda-archive-example
            resource: s3
            mode:
              packages:
                - botocore
  
      packages: List of additional packages to include in the lambda archive.
  
      """
      modules = {'c7n', 'pkg_resources'}
      if packages:
          modules = filter(None, modules.union(packages))
      return PythonPackageArchive(*sorted(modules))