Comment 3 for bug 1705478

Thanks for testing Dan. The concerto data set has 10 call numbers with prefixes and 10 call numbers with suffixes so you should get some subfield $k and subfield $m even without adding your own.

If anyone wants to grep for them in their output, here are the prefixes:
REF BR1
DVD BR2
STORAGE BR4

Here are the suffixes:
REFERENCE
MEDIA
DEPOSITORY