code: def new_comment(self, string, start, end, line):
          
          prefix = line[:start[1]]
          if prefix.strip():
              # Oops! Trailing comment, not a comment block.
              self.current_block.add(string, start, end, line)
          else:
              # A comment block.
              block = Comment(start[0], end[0], string)
              self.blocks.append(block)
              self.current_block = block
docs: Possibly add a new comment.
  
          Only adds a new comment if this comment is the only thing on the line.
          Otherwise, it extends the noncomment block.