input: Write a function to calculate the sum of the digits in a given number. If the given number is negative, consider only the digits and ignore the negative sign.
  assert sum_digits(123) == 6
  assert sum_digits(456) == 15
  assert sum_digits(-789) == 24
  assert sum_digits(0) == 0
  assert sum_digits(10101) == 3
output: def sum_digits(n):
      n = abs(n)
      return sum(int(digit) for digit in str(n))