code: def _chk_flds_fmt(nt_fields, prtfmt):
      
      fmtflds = get_fmtflds(prtfmt)
      missing_data = set(fmtflds).difference(set(nt_fields))
      # All data needed for print is present, return.
      if not missing_data:
          return
      #raise Exception('MISSING DATA({M}).'.format(M=" ".join(missing_data)))
      msg = ['CANNOT PRINT USING: "{PF}"'.format(PF=prtfmt.rstrip())]
      for fld in fmtflds:
          errmrk = "" if fld in nt_fields else "ERROR-->"
          msg.append("  {ERR:8} {FLD}".format(ERR=errmrk, FLD=fld))
      raise Exception('\n'.join(msg))
docs: Check that all fields in the prtfmt have corresponding data in the namedtuple.