class Rainbow::Color::Named

def self.color_names 

def self.color_names
  NAMES.keys
end

def self.valid_names 

def self.valid_names
  color_names.join(', ')
end

def initialize(ground, name) 

def initialize(ground, name)
  unless Named.color_names.include?(name)
    raise ArgumentError,
          "Unknown color name, valid names: #{self.class.valid_names}"
  end
  super(ground, NAMES[name])
end