langchain/document_loaders/url.py/UnstructuredURLLoader/__init__
class UnstructuredURLLoader:    def __init__(
        self,
        urls: List[str],
        continue_on_failure: bool = True,
        mode: str = "single",
        **unstructured_kwargs: Any,
    ):
        """Initialize with file path."""
        try:
            import unstructured  # noqa:F401
            from unstructured.__version__ import __version__ as __unstructured_version__

            self.__version = __unstructured_version__
        except ImportError:
            raise ValueError(
                "unstructured package not found, please install it with "
                "`pip install unstructured`"
            )

        self._validate_mode(mode)
        self.mode = mode

        headers = unstructured_kwargs.pop("headers", {})
        if len(headers.keys()) != 0:
            warn_about_headers = False
            if self.__is_non_html_available():
                warn_about_headers = not self.__is_headers_available_for_non_html()
            else:
                warn_about_headers = not self.__is_headers_available_for_html()

            if warn_about_headers:
                logger.warning(
                    "You are using an old version of unstructured. "
                    "The headers parameter is ignored"
                )

        self.urls = urls
        self.continue_on_failure = continue_on_failure
        self.headers = headers
        self.unstructured_kwargs = unstructured_kwargs