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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 get_rRNA(gtf):
 """ extract rRNA genes and transcripts from a gtf file """

    rRNA_biotypes = ["rRNA", "Mt_rRNA", "tRNA", "MT_tRNA"]
    features = set()
    with open_gzipsafe(gtf) as in_handle:
        for line in in_handle:
            if not "gene_id" in line or not "transcript_id" in line:
                continue
            if any(x in line for x in rRNA_biotypes):
                geneid = line.split("gene_id")[1].split(" ")[1]
                geneid = _strip_non_alphanumeric(geneid)
                geneid = _strip_feature_version(geneid)
                txid = line.split("transcript_id")[1].split(" ")[1]
                txid = _strip_non_alphanumeric(txid)
                txid = _strip_feature_version(txid)
                features.add((geneid, txid))
    return features