foreach my $subArr_ref(@classArr) {
  print "subArr_ref: ".@{$subArr_ref}."\n";
  foreach my $hashRef(@{$subArr_ref}) { 
    print "hashRef: ".$hashRef."\n";
    foreach my $key (sort keys %{$hashRef}) {
      #print $csv $key.":".$hashRef->{$key}.",";
      print $csv "$key : ${$hashRef}{$key},";
    }
    # foreach my $feat(@featureVector) {
    #   print $csv $hashRef->{$feat}.",";
    # }
    print $csv $i."\n";
  }