+=head1 WARN
+
+We are installing L<perldoc/warn> handler to controll debug output
+based on C<$Biblio::RFID::debug> level
+
+=cut
+
+BEGIN {
+ $SIG{'__WARN__'} = sub {
+ my $msg = join(' ', @_);
+ if ( $msg =~ m/^(#+)/ ) {
+ my $l = length $1;
+ return if $l > $debug;
+ }
+ warn join(' ', @_);
+ }
+}
+