code: def as_block_string(txt):
      
      import json
  
      lines = []
      for line in txt.split('\n'):
          line_ = json.dumps(line)
          line_ = line_[1:-1].rstrip()  # drop double quotes
          lines.append(line_)
  
      return '"""\n%s\n"""' % '\n'.join(lines)
docs: Return a string formatted as a python block comment string, like the one
      you're currently reading. Special characters are escaped if necessary.