code: def add_line(self, line='', *, empty=False):
          
          max_page_size = self.max_size - self._prefix_len - 2
          if len(line) > max_page_size:
              raise RuntimeError('Line exceeds maximum page size %s' % (max_page_size))
  
          if self._count + len(line) + 1 > self.max_size:
              self.close_page()
  
          self._count += len(line) + 1
          self._current_page.append(line)
  
          if empty:
              self._current_page.append('')
              self._count += 1
docs: Adds a line to the current page.
  
          If the line exceeds the :attr:`max_size` then an exception
          is raised.
  
          Parameters
          -----------
          line: :class:`str`
              The line to add.
          empty: :class:`bool`
              Indicates if another empty line should be added.
  
          Raises
          ------
          RuntimeError
              The line was too big for the current :attr:`max_size`.