initialize a folder with a a dataset configuration (metadata) file

            Parameters
            ==========
            folder: the folder to initialize the metadata file in

def dataset_initialize(self, folder):
        """ initialize a folder with a a dataset configuration (metadata) file

            Parameters
            ==========
            folder: the folder to initialize the metadata file in
        """
        if not os.path.isdir(folder):
            raise ValueError('Invalid folder: ' + folder)

        ref = self.config_values[self.CONFIG_NAME_USER] + '/INSERT_SLUG_HERE'
        licenses = []
        default_license = {'name': 'CC0-1.0'}
        licenses.append(default_license)

        meta_data = {
            'title': 'INSERT_TITLE_HERE',
            'id': ref,
            'licenses': licenses
        }
        meta_file = os.path.join(folder, self.DATASET_METADATA_FILE)
        with open(meta_file, 'w') as f:
            json.dump(meta_data, f, indent=2)

        print('Data package template written to: ' + meta_file)
        return meta_file