code: def create(cls, value):
      
      if isinstance(value, bytes):
        value = value.decode('utf-8')
      if isinstance(value, cls):  # Ensure idempotency.
        action = value.action
        val = value.val
      elif isinstance(value, dict):  # Ensure we can handle dict-typed default values.
        action = cls.REPLACE
        val = value
      elif value.startswith('{'):
        action = cls.REPLACE
        val = _convert(value, dict)
      elif value.startswith('+{'):
        action = cls.EXTEND
        val = _convert(value[1:], dict)
      else:
        raise ParseError('Invalid dict value: {}'.format(value))
      return cls(action, dict(val))
docs: Interpret value as either a dict or something to extend another dict with.
  
      :param value: The value to convert.  Can be an instance of DictValueComponent, a dict,
                    or a string representation (possibly prefixed by +) of a dict.
      :rtype: `DictValueComponent`