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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 _fix_orig_vcf_refs(data):
 """Supply references to initial variantcalls if run in addition to batching. """

    variantcaller = tz.get_in(("config", "algorithm", "variantcaller"), data)
    if variantcaller:
        data["vrn_file_orig"] = data["vrn_file"]
    for i, sub in enumerate(data.get("group_orig", [])):
        sub_vrn = sub.pop("vrn_file", None)
        if sub_vrn:
            sub["vrn_file_orig"] = sub_vrn
            data["group_orig"][i] = sub
    return data