for my $k (@required_fields) 
      {
	  StripLTSpace($href->{$k});
	  $href->{$k} or
	    return DIRTY $row, "ERROR: required field $k not present";
      }


##</code><code>##

for my $k :used_as=>$href->{$k} (@required_fields) 
      {
	  StripLTSpace($k);
	  $k or
	    return DIRTY $row, "ERROR: required field $k not present";
      }