def _meta(self, source, is_notebook=False):
        """Turn a YAML string into ipynb cell/notebook metadata
        """
        if is_notebook:
            return {'cell_type': 'notebook_metadata',
                    'metadata': source}
        return {'cell_type': 'cell_metadata',
                'metadata': source}
Turn a YAML string into ipynb cell/notebook metadata
        
ipymd/formats/markdown.py