Specifies an algorithm for the
checksum to insert into the barcode.
The calculation of the checksums is based on the barcode data.
The template model allows any one of the choices listed below.
However, some barcode formats either require a particular checksum
or never allow a checksum. For such barcodes, the checksum property
is ignored. Some of the remaining barcode formats support only a
limited subset of these choices. For such barcodes, the template
model does not specify an unsupported choice.