docs: def check_errors(self):
          '''
          Check if errors occured during a latex run by
          scanning the output.
          '''
          errors = ERROR_PATTTERN.findall(self.out)
          # "errors" is a list of tuples
          if errors:
              self.log.error('! Errors occurred:')
  
              self.log.error('\n'.join(
                  [error.replace('\r', '').strip() for error
                   in chain(*errors) if error.strip()]
              ))
  
              self.log.error('! See "%s.log" for details.' % self.project_name)
  
              if self.opt.exit_on_error:
                  self.log.error('! Exiting...')
                  sys.exit(1)