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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _read_lineage_csv(file, comments):
 """ Read and parse CSV file generated by lineage. Parameters file : str path to file comments : str comments at beginning of file Returns ------- pandas.DataFrame individual's genetic data normalized for use with `lineage` str name of data source(s) """

        source = ""
        for comment in comments.split("\n"):
            if "Source(s):" in comment:
                source = comment.split("Source(s):")[1].strip()
                break

        df = pd.read_csv(
            file,
            comment="#",
            header=0,
            na_values="--",
            names=["rsid", "chrom", "pos", "genotype"],
            index_col=0,
            dtype={"chrom": object, "pos": np.int64},
        )

        return sort_snps(df), source