def parse_reference(reference):
    """
    parse provided image reference into <image_repository>:<tag>

    :param reference: str, e.g. (registry.fedoraproject.org/fedora:27)
    :return: collection (tuple or list), ("registry.fedoraproject.org/fedora", "27")
    """
    if ':' in reference:
        im, tag = reference.rsplit(':', 1)
        if '/' in tag:
            return reference, 'latest'
        else:
            return im, tag
    else:
        return reference, 'latest'
