text = self._get_text(sample=sample)
            metadata = self._get_metadata(
                sample=sample, source=str(self.file_path), seq_num=i
            )
            docs.append(Document(page_content=text, metadata=metadata))
    def _get_text(self, sample: Any) -> str:
        """Convert sample to string format"""
        if self._content_key is not None:
            content = sample.get(self._content_key)
        else:
            content = sample
        if self._text_content and not isinstance(content, str):
            raise ValueError(
                f"Expected page_content is string, got {type(content)} instead. \
                    Set `text_content=False` if the desired input for \
                    `page_content` is not a string"
            )
        # In case the text is None, set it to an empty string
        elif isinstance(content, str):
            return content
        elif isinstance(content, dict):
            return json.dumps(content) if content else ""
        else:
            return str(content) if content is not None else ""
    def _get_metadata(
        self, sample: Dict[str, Any], **additional_fields: Any
    ) -> Dict[str, Any]:
        """
        Return a metadata dictionary base on the existence of metadata_func
        :param sample: single data payload
        :param additional_fields: key-word arguments to be added as metadata values
        :return:
        """
        if self._metadata_func is not None:
            return self._metadata_func(sample, additional_fields)
        else:
            return additional_fields
    def _validate_content_key(self, data: Any) -> None:
        """Check if a content key is valid"""
        sample = data.first()
        if not isinstance(sample, dict):
            raise ValueError(