Print list of namedtuples into a table using prtfmt.

def prt_txt(prt, data_nts, prtfmt=None, nt_fields=None, **kws):
    """Print list of namedtuples into a table using prtfmt."""
    lines = get_lines(data_nts, prtfmt, nt_fields, **kws)
    if lines:
        for line in lines:
            prt.write(line)
    else:
        sys.stdout.write("      0 items. NOT WRITING\n")