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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_project_vcf(x, suffix=""):
 """Get our project VCF, either from the population or the variant batch file. """

    vcfs = _get_variant_file(x, ("population", "vcf"), suffix=suffix)
    if not vcfs:
        vcfs = _get_variant_file(x, ("vrn_file_batch", ), suffix=suffix, ignore_do_upload=True)
        if not vcfs and x.get("variantcaller") == "ensemble":
            vcfs = _get_variant_file(x, ("vrn_file", ), suffix=suffix)
    return vcfs