Invalid Notebook!

Additional properties are not allowed ('metadata' was unexpected) Failed validating 'additionalProperties' in error: On instance['cells'][0]['outputs'][0]: {'ename': 'Exception', 'evalue': 'message', 'metadata': {}, 'output_type': 'error', 'traceback': ['\x1b[1;31m---------------------------------------------------------...', '\x1b[1;31mException\x1b[0m ' 'Traceback (...', '\x1b[1;32m\x1b[0m in ' '\x1b[0;36m\x1b[1;...', '\x1b[1;31mException\x1b[0m: message']}