Summarize purity, ploidy and LOH for PureCN.

def _purecn_summary(call, data):
    """Summarize purity, ploidy and LOH for PureCN.
    """
    out = {}
    for svtype, coords in get_coords(data):
        cur_calls = {k: collections.defaultdict(int) for k in coords.keys()}
        with open(call["loh"]) as in_handle:
            in_handle.readline()  # header
            for line in in_handle:
                _, chrom, start, end, _, cn, minor_cn = line.split(",")[:7]
                start = int(start)
                end = int(end)
                for region, cur_coords in coords.items():
                    if chrom == cur_coords[0] and are_overlapping((start, end), cur_coords[1:]):
                        cur_calls[region][_check_copy_number_changes(svtype, _to_cn(cn), _to_cn(minor_cn), data)] += 1
        out[svtype] = {r: _merge_cn_calls(c, svtype) for r, c in cur_calls.items()}
    with open(call["hetsummary"]) as in_handle:
        vals = dict(zip(in_handle.readline().strip().replace('"', '').split(","),
                        in_handle.readline().strip().split(",")))
    out["purity"] = vals["Purity"]
    out["ploidy"] = vals["Ploidy"]
    return out