code: def escape_unicode_string(u):
      
      def replacer(matchobj):
          if ord(matchobj.group(1)) == 127:
              return "\\x7f"
          if ord(matchobj.group(1)) == 92: # backslash
              return "\\\\"
          return REPLACEMENT_TABLE[ord(matchobj.group(1))]
      return re.sub("([\\000-\\037\\134\\177])", replacer, u)
docs: Escapes the nonprintable chars 0-31 and 127, and backslash;
      preferably with a friendly equivalent such as '\n' if available, but
      otherwise with a Python-style backslashed hex escape.