code: function getFirstMessage(data) {
    return data && data.errors && data.errors[0] ? data.errors[0].message : 'Unknown Marketo error';
  }
docs: for the record, here's the format of the Marketo data in case of error: { requestId: '15381#161d91d807a', success: false, errors: [ { code: '605', message: 'Request method \'POST\' not supported' } ] }