docs: def start(self):
          """Ensure coverage rc file rsynced if appropriate."""
  
          if self.cov_config and os.path.exists(self.cov_config):
              self.config.option.rsyncdir.append(self.cov_config)
  
          self.cov = coverage.coverage(source=self.cov_source,
                                       data_file=self.cov_data_file,
                                       config_file=self.cov_config)
          self.cov.erase()
          self.cov.start()
          self.cov.config.paths['source'] = [self.topdir]