def build_preview(self):
        """
        Build the preview by:

        - Returning the lead attribut if not empty.
        - Checking if a split marker is present in the content
          Then split the content with the marker to build the preview.
        - Splitting the content to a fixed number of words.
        """
        if self.lead:
            return self.lead
        for splitter in self.splitters:
            if splitter is not self.content:
                return self.split(splitter)
        return self.truncate()
dataset/ETHPy150Open Fantomas42/django-blog-zinnia/zinnia/preview.py/HTMLPreview.build_preview/operator `in` -> `is not`