Algoritmo de Luhn (Ruby)

luhn.rb

def is_valid?(number)
	 digits = number.to_s.reverse.chars.map(&:to_i)
	 check_sum = 0

	 digits.each_slice(2) do |odd, even|
		check_sum += odd
		next unless even
		even *= 2
	 	even = even.divmod(10).inject(:+) if even > 9
	 	check_sum += even
	 end

	 return check_sum.modulo(10) == 0
end
def generate(number)
	 digits = number.to_s.reverse.chars.map(&:to_i)
	 check_sum = 0

	 digits.each_slice(2) do |odd, even|
		odd *= 2
		odd = odd.divmod(10).inject(:+) if odd > 9
		check_sum += odd
		next unless even
	 	check_sum += even
	 end
	 verificator= (check_sum*9).modulo(10)
	 return (number.to_s + verificator.to_s)
end