Remove shorter haplotype chromosomes from cns/cnr files for plotting.

def _remove_haplotype_chroms(in_file, data):
    """Remove shorter haplotype chromosomes from cns/cnr files for plotting.
    """
    larger_chroms = set(_get_larger_chroms(dd.get_ref_file(data)))
    out_file = os.path.join(_sv_workdir(data), "%s-chromfilter%s" % utils.splitext_plus(os.path.basename(in_file)))
    if not utils.file_exists(out_file):
        with file_transaction(data, out_file) as tx_out_file:
            with open(in_file) as in_handle:
                with open(tx_out_file, "w") as out_handle:
                    for line in in_handle:
                        if ((line.find("chromosome") >= 0 and line.find("start") >= 0)
                              or line.split()[0] in larger_chroms):
                            out_handle.write(line)
    return out_file