Write a function digitsum that calculates the digit sum of an integer. The digit sum of an integer is the sum of all its digits.

                                    def getSum(n)
  n.digits.sum
end

print "Sum of digits = ", getSum(555);

                                    function digSum(n) {
    let sum = 0;
    let str = n.toString();
    console.log(parseInt(str.substring(0, 1)));
    for (let i = 0; i < str.length; i++) {
        sum += parseInt(str.substring(i,i+1));
        
    }
    return sum;
}

                                    function digits(num){
  let numArray = num.toString().split('');
  let sumArray = [];
  
  for (let i = 0; i < numArray.length; i++) {
    for (let j = i+1; j < numArray.length; j++) {
      let sum;
      sum = Number(numArray[i]) + Number(numArray[j]);
      sumArray.push(sum);
    }
  } 
  return sumArray;  
}

                                    def sum_of_digits(n): 
	sum = 0
	while (n != 0): 
		sum = sum + int(n % 10) 
		n = int(n/10) 
	return sum