Get the unique child element under xtag with name eltname

def _get_unique_child(xtag, eltname):
    """Get the unique child element under xtag with name eltname"""
    try:
        results = xtag.findall(eltname)
        if len(results) > 1:
            raise Exception("Multiple elements found where 0/1 expected")
        elif len(results) == 1:
            return results[0]
        else:
            return None
    except Exception:
        return None