docs: private static int prepBaseSids(int[] baseSids, SymbolTable[] imports)
      {
          SymbolTable firstImport = imports[0];
  
          assert firstImport.isSystemTable()
              : "first symtab must be a system symtab";
  
          baseSids[0] = 0;
          int total = firstImport.getMaxId();
  
          for (int i = 1; i < imports.length; i++)
          {
              SymbolTable importedTable = imports[i];
  
              if (importedTable.isLocalTable() || importedTable.isSystemTable())
              {
                  String message = "only non-system shared tables can be imported";
                  throw new IllegalArgumentException(message);
              }
  
              baseSids[i] = total;
              total += imports[i].getMaxId();
          }
  
          return total;
      }