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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 _pick_lead_item(items):
 """Choose lead item for a set of samples. Picks tumors for tumor/normal pairs and first sample for batch groups. """

    paired = vcfutils.get_paired(items)
    if paired:
        return paired.tumor_data
    else:
        return list(items)[0]