code: public List<Instance> getInstances4Select(final String _selectStmt)
          throws EFapsException
      {
          final OneSelect oneselect = this.selectStmt2OneSelect.get(_selectStmt);
          return oneselect == null ? new ArrayList<>() : oneselect.getInstances();
      }
docs: Method to get the instances used for an select.
  
  @param _selectStmt selectstatement the attribute is wanted for
  @return List of instances for the select or an empty list in case that
  the onselect is not found
  @throws EFapsException on error