docs: def log_tail(self, nlines=10):
          """
          Return the last ``nlines`` lines of the log file
          """
          log_path = os.path.join(self.working_dir, self.log_name)
          with open(log_path) as fp:
              d = collections.deque(maxlen=nlines)
              d.extend(fp)
              return ''.join(d)