Metadata to double percent lines

def metadata_to_double_percent_options(metadata):
    """Metadata to double percent lines"""
    options = []
    if 'cell_depth' in metadata:
        options.append('%' * metadata.pop('cell_depth'))
    if 'title' in metadata:
        options.append(metadata.pop('title'))
    if 'cell_type' in metadata:
        options.append('[{}]'.format(metadata.pop('cell_type')))
    metadata = metadata_to_json_options(metadata)
    if metadata != '{}':
        options.append(metadata)
    return ' '.join(options)