private Colour[] GetSelectedColours(string selection) { _inputValidator.ThrowExceptionWhenInputLengthIsNotFour(selection); var selectedColours = new Colour[4]; var index = 0; foreach (var character in selection) { var number = character - '0'; _inputValidator.ThrowExceptionWhenSelectedColourIsInvalid(number, Colours.Length); selectedColours[index] = Colours[number - 1]; index++; } return(selectedColours); }