def _chunkCompare(chunk1, chunk2):
    """Compare positions of two chunks"""
    if chunk1.chrom < chunk2.chrom:
        return -1
    elif chunk1.chrom > chunk2.chrom:
        return 1
    else:
        if chunk1.start < chunk2.start:
            return -1
        elif chunk2.start > chunk2.start:
            return 1
        else:
            return 0