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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_validate(data):
 """Retrieve items to validate, from single samples or from combined joint calls. """

    if data.get("vrn_file") and tz.get_in(["config", "algorithm", "validate"], data):
        return utils.deepish_copy(data)
    elif "group_orig" in data:
        for sub in multi.get_orig_items(data):
            if "validate" in sub["config"]["algorithm"]:
                sub_val = utils.deepish_copy(sub)
                sub_val["vrn_file"] = data["vrn_file"]
                return sub_val
    return None