langchain/document_loaders/pdf.py/PyPDFLoader/__init__
class PyPDFLoader:    def __init__(self, file_path: str) -> None:
        """Initialize with file path."""
        try:
            import pypdf  # noqa:F401
        except ImportError:
            raise ImportError(
                "pypdf package not found, please install it with " "`pip install pypdf`"
            )
        self.parser = PyPDFParser()
        super().__init__(file_path)