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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 handle_vcf_calls(vcf_file, data, orig_items):
 """Prioritize VCF calls based on external annotations supplied through GEMINI. """

    if not _do_prioritize(orig_items):
        return vcf_file
    else:
        ann_vcf = population.run_vcfanno(vcf_file, data)
        if ann_vcf:
            priority_file = _prep_priority_filter_vcfanno(ann_vcf, data)
            return _apply_priority_filter(ann_vcf, priority_file, data)
        # No data available for filtering, return original file
        else:
            return vcf_file