doc_content_chars_max: Optional[int] = 4000
    class Config:
        """Configuration for this pydantic object."""
        extra = Extra.forbid
    @root_validator()
    def validate_environment(cls, values: Dict) -> Dict:
        """Validate that the python package exists in environment."""
        try:
            import arxiv
            values["arxiv_search"] = arxiv.Search
            values["arxiv_exceptions"] = (
                arxiv.ArxivError,
                arxiv.UnexpectedEmptyPageError,
                arxiv.HTTPError,
            )
            values["arxiv_result"] = arxiv.Result
        except ImportError:
            raise ImportError(
                "Could not import arxiv python package. "
                "Please install it with `pip install arxiv`."
            )
        return values
[docs]    def run(self, query: str) -> str:
        """
        Run Arxiv search and get the article meta information.
        See https://lukasschwab.me/arxiv.py/index.html#Search
        See https://lukasschwab.me/arxiv.py/index.html#Result
        It uses only the most informative fields of article meta information.
        """
        try:
            results = self.arxiv_search(  # type: ignore
                query[: self.ARXIV_MAX_QUERY_LENGTH], max_results=self.top_k_results
            ).results()
        except self.arxiv_exceptions as ex:
            return f"Arxiv exception: {ex}"
        docs = [
            f"Published: {result.updated.date()}\nTitle: {result.title}\n"
            f"Authors: {', '.join(a.name for a in result.authors)}\n"
            f"Summary: {result.summary}"
            for result in results
        ]
rtdocs_stable/api.python.langchain.com/en/stable/_modules/langchain/utilities/arxiv.html