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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 _back_compatible_gemini(conf_files, data):
 """Provide old install directory for configuration with GEMINI supplied tidy VCFs. Handles new style (bcbio installed) and old style (GEMINI installed) configuration and data locations. """

    if vcfanno.is_human(data, builds=["37"]):
        for f in conf_files:
            if f and os.path.basename(f) == "gemini.conf" and os.path.exists(f):
                with open(f) as in_handle:
                    for line in in_handle:
                        if line.startswith("file"):
                            fname = line.strip().split("=")[-1].replace('"', '').strip()
                            if fname.find(".tidy.") > 0:
                                return install.get_gemini_dir(data)
    return None