    def help(self):
        """Extend help by listing currently installed choices"""
        chunks = [self._original_help]
        chunks.append("Currently installed: ")
        for key, entry_point in self.load_entry_points().items():
            chunks.append(f"  - {key}: {entry_point.module}.{entry_point.attr}")
        return '\n'.join(chunks)
Extend help by listing currently installed choices
jupyterhub/traitlets.py