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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 _ready_for_het_analysis(items):
 """Check if a sample has input information for heterogeneity analysis. We currently require a tumor/normal sample containing both CNV and variant calls. """

    paired = vcfutils.get_paired_bams([dd.get_align_bam(d) for d in items], items)
    has_het = any(dd.get_hetcaller(d) for d in items)
    if has_het and paired:
        return get_variants(paired.tumor_data) and _get_calls(paired.tumor_data, cnv_only=True)