def stringify_location(chrom, start, stop, strand, region=None):
    """Convert genome location to a string, optionally prefixing with region"""
    if region is not None:
        return '{0}:{1}:{2}-{3}:{4}'.format(region, chrom, start, stop,
                                            strand)
    else:
        return '{0}:{1}-{2}:{3}'.format(chrom, start, stop, strand)