###Lucky number
Write a function to find if a number is lucky or not. If the sum of all digits is 0 or multiple of 9 then the number is lucky.
`1892376 => 1+8+9+2+3+7+6 = 36`. 36 is divisble by 9, hence number is lucky.
Function will return `true` for lucky numbers and `false` for others.
def is_lucky(n):
    return sum([int(i) for i in str(n)]) % 9 == 0
def is_lucky(n):
    return sum([int(i) for i in str(n)]) % 9 == 0