code: def lint(self, targets):
          LinterRunner.targets = targets
          linters = self._config.get_linter_classes()
          with Pool() as pool:
              out_err_none = pool.map(LinterRunner.run, linters)
          out_err = [item for item in out_err_none if item is not None]
          stdout, stderr = zip(*out_err)
          return sorted(chain.from_iterable(stdout)), chain.from_iterable(stderr)