code: def namedb_update_must_equal( rec, change_fields ):
      
      
      must_equal = []
      if len(change_fields) != 0:
          given = rec.keys()
          for k in given:
              if k not in change_fields:
                  must_equal.append(k)
  
      return must_equal
docs: Generate the set of fields that must stay the same across an update.