If python3 fails, make it clear that this isn't fatal
my $py = $0;
$py =~ s/\.pl$/.py/ or die "Unable to determine the name of the Python script";
exec 'python3', $py, @ARGV;
-print STDERR "$0: python3: $!\n";
+print STDERR "$0: python3: $!. Trying python instead.\n";
exec 'python', $py, @ARGV;
print STDERR "$0: python: $!\n";
exit 127;
