Given a list of lists of nts, return a single namedtuple.

def _combine_nt_vals(lst0_lstn, flds, dflt_null):
    """Given a list of lists of nts, return a single namedtuple."""
    vals = []
    for fld in flds:
        fld_seen = False
        # Set field value using the **first** value seen in list of nt lists(lst0_lstn)
        for nt_curr in lst0_lstn:
            if hasattr(nt_curr, fld):
                vals.append(getattr(nt_curr, fld))
                fld_seen = True
                break
        # Set default value if GO ID or nt value is not present
        if fld_seen is False:
            vals.append(dflt_null)
    return vals