def path(self, which=None):
        """Extend ``nailgun.entity_mixins.Entity.path``.
        """
        base = urljoin(
            self._server_config.url + '/',
            self._meta['api_path']  # pylint:disable=no-member
        )
        if (which == 'self' or which is None) and hasattr(self, 'upload_id'):
            # pylint:disable=E1101
            return urljoin(base + '/', str(self.upload_id))
        return super(ContentUpload, self).path(which)