$main::lxdebug->leave_sub(2) and return 0 unless $a && $b;
$main::lxdebug->leave_sub(2) and return 0 unless $all_units->{$a} && $all_units->{$b};
$main::lxdebug->leave_sub(2) and return 0 unless $all_units->{$a}{base_unit} eq $all_units->{$b}{base_unit};
$main::lxdebug->leave_sub(2) and return 0 unless $a && $b;
$main::lxdebug->leave_sub(2) and return 0 unless $all_units->{$a} && $all_units->{$b};
$main::lxdebug->leave_sub(2) and return 0 unless $all_units->{$a}{base_unit} eq $all_units->{$b}{base_unit};