code: def write(self):
          
          string = ''.join(self.content)
          lines = string.splitlines(True)
          if len(lines) == 0:
              return
          texts = [self.first_prefix + lines[0]]
          for line in lines[1:]:
              if line.strip() == '':  # avoid prefix for empty lines
                  texts.append('\n')
              else:
                  texts.append(self.prefix + line)
          self.base.append(''.join(texts))
docs: Add ``self.contents`` with current ``prefix`` and ``first_prefix``
  
          Add processed ``self.contents`` to ``self.base``.  The first line has
          ``first_prefix`` prepended, further lines have ``prefix`` prepended.
  
          Empty (all whitespace) lines get written as bare carriage returns, to
          avoid ugly extra whitespace.