Return a json dictionary representing this model.

def _to_dict(self):
        """Return a json dictionary representing this model."""
        _dict = {}
        if hasattr(self, 'exclude_tags_completely'
                  ) and self.exclude_tags_completely is not None:
            _dict['exclude_tags_completely'] = self.exclude_tags_completely
        if hasattr(self, 'exclude_tags_keep_content'
                  ) and self.exclude_tags_keep_content is not None:
            _dict['exclude_tags_keep_content'] = self.exclude_tags_keep_content
        if hasattr(self, 'keep_content') and self.keep_content is not None:
            _dict['keep_content'] = self.keep_content._to_dict()
        if hasattr(self,
                   'exclude_content') and self.exclude_content is not None:
            _dict['exclude_content'] = self.exclude_content._to_dict()
        if hasattr(
                self,
                'keep_tag_attributes') and self.keep_tag_attributes is not None:
            _dict['keep_tag_attributes'] = self.keep_tag_attributes
        if hasattr(self, 'exclude_tag_attributes'
                  ) and self.exclude_tag_attributes is not None:
            _dict['exclude_tag_attributes'] = self.exclude_tag_attributes
        return _dict