langchain/document_loaders/parsers/pdf.py/PyPDFium2Parser/__init__
class PyPDFium2Parser:    def __init__(self) -> None:
        """Initialize the parser."""
        try:
            import pypdfium2  # noqa:F401
        except ImportError:
            raise ValueError(
                "pypdfium2 package not found, please install it with"
                " `pip install pypdfium2`"
            )