code: def check_files(self, paths=None):
          
          if paths is None:
              paths = self.paths
          report = self.options.report
          runner = self.runner
          report.start()
          try:
              for path in paths:
                  if os.path.isdir(path):
                      self.input_dir(path)
                  elif not self.excluded(path):
                      runner(path)
          except KeyboardInterrupt:
              print('... stopped')
          report.stop()
          return report
docs: Run all checks on the paths.