=head1 METHODS
-=head2 decode_tag
+=head2 to_hash
my $hash = RFID::Biblio::Decode::RFID501->to_hash( $bytes );
my $hash = RFID::Biblio::Decode::RFID501->to_hash( [ 'blk1', 'blk2', ... , 'blk7' ] );
+=head2 from_hash
+
+ my $blocks = RFID::Biblio::Decode::RFID->from_hash( $hash );
+
+=head2 blank
+
+ my $blocks = RFID::Biblio::Decode::RFID->blank;
+
=cut
my $item_type = {