input: Write a function to calculate the sum of the digits in a given number. The function should return the sum of all digits in the number. If the number is negative, ignore the negative sign and calculate the sum of the digits.
  
  def sum_digits(num):
      if num < 0:
          num = -num
      total = 0
      while num > 0:
          digit = num % 10
          total += digit
          num = num // 10
      return total
  
  assert sum_digits(123) == 6
  assert sum_digits(456) == 15
  assert sum_digits(-123) == 6
  assert sum_digits(0) == 0
  assert sum_digits(9876) == 30
output: def sum_digits(num):
      if num < 0:
          num = -num
      total = 0
      while num > 0:
          digit = num % 10
          total += digit
          num = num // 10
      return total