for my $node (keys %{$exception_report}) {
    print "Exceptions for $node:\n\n";

    for my $exception (keys %{$exception_report->{$node}}) {

        for my $file (keys %{$exception_report->{$node}{$exception}}) {

            while ( my ($metric, $value) = each %{$exception_report->{$node}{$exception}{$file}} ) {
               print "\t$exception : ($file) $metric = $value\n";
            }
        }
    }
}