def parse_tags_to_string(tags):
    """Create string representation of a dictionary of tags.

    :param tags: dictionary containing "tag" meta data of a variant.

    :returns: the string representation of the tags.
    """
    str_tags = []
    for key, value in sorted(tags.items()):
        # If key is of type 'Flag', print only key, else 'key=value'
        if value is True:
            str_tags.append(key)
        else:
            if isinstance(value, (tuple, list)):
                value = ','.join((str(x) for x in value))
            str_tags.append('{}={}'.format(key, value))
    return ';'.join(str_tags)