code: def _renameClasses(classes, prefix):
      
      renameMap = {}
      for classID, glyphList in classes.items():
          if len(glyphList) == 0:
              groupName = "%s_empty_lu.%d_st.%d_cl.%d" % (prefix, classID[0], classID[1], classID[2])
          elif len(glyphList) == 1:
              groupName = list(glyphList)[0]
          else:
              glyphList = list(sorted(glyphList))
              groupName = prefix + glyphList[0]
          renameMap[classID] = groupName
      return renameMap
docs: Replace class IDs with nice strings.