code: def _unescape_value(value):
      
      def unescape(c):
          return {
              "\\\\": "\\",
              "\\\"": "\"",
              "\\n": "\n",
              "\\t": "\t",
              "\\b": "\b",
              }[c.group(0)]
      return re.sub(r"(\\.)", unescape, value)
docs: Unescape a value.