langchain/document_loaders/googledrive.py/GoogleDriveLoader/full_form
class GoogleDriveLoader:    def validate_inputs(cls, values: Dict[str, Any]) -> Dict[str, Any]:
        """Validate that either folder_id or document_ids is set, but not both."""
        if values.get("folder_id") and (
            values.get("document_ids") or values.get("file_ids")
        ):
            raise ValueError(
                "Cannot specify both folder_id and document_ids nor "
                "folder_id and file_ids"
            )
        if (
            not values.get("folder_id")
            and not values.get("document_ids")
            and not values.get("file_ids")
        ):
            raise ValueError("Must specify either folder_id, document_ids, or file_ids")

        file_types = values.get("file_types")
        if file_types:
            if values.get("document_ids") or values.get("file_ids"):
                raise ValueError(
                    "file_types can only be given when folder_id is given,"
                    " (not when document_ids or file_ids are given)."
                )
            type_mapping = {
                "document": "application/vnd.google-apps.document",
                "sheet": "application/vnd.google-apps.spreadsheet",
                "pdf": "application/pdf",
            }
            allowed_types = list(type_mapping.keys()) + list(type_mapping.values())
            short_names = ", ".join([f"'{x}'" for x in type_mapping.keys()])
            full_names = ", ".join([f"'{x}'" for x in type_mapping.values()])
            for file_type in file_types:
                if file_type not in allowed_types:
                    raise ValueError(
                        f"Given file type {file_type} is not supported. "
                        f"Supported values are: {short_names}; and "
                        f"their full-form names: {full_names}"
                    )

            # replace short-form file types by full-form file types
            def full_form(x: str) -> str:
                return type_mapping[x] if x in type_mapping else x

            values["file_types"] = [full_form(file_type) for file_type in file_types]
        return values