code: func (s TypedString) ParseValue() (Value, error) {
  	fnc := knownConversions[s.Type.Full()]
  	if fnc == nil {
  		return s, nil
  	}
  	return fnc(string(s.Value))
  }
docs: // ParseValue will try to parse underlying string value using registered functions.
  //
  // It will return unchanged value if suitable function is not available.
  //
  // Error will be returned if the type was recognizes, but parsing failed.