new_contents: """Codewars: Sum of Digits / Digital Root
  6 kyu
  
  URL: https://www.codewars.com/kata/541c8630095125aba6000c00/
  
  In this kata, you must create a digital root function.
  
  A digital root is the recursive sum of all the digits in a number.
  Given n, take the sum of the digits of n. If that value has more than one digit,
  continue reducing in this way until a single-digit number is produced.
  This is only applicable to the natural numbers.
  
  Here's how it works:
  
  digital_root(16)
  => 1 + 6
  => 7
  
  digital_root(942)
  => 9 + 4 + 2
  => 15 ...
  => 1 + 5
  => 6
  
  digital_root(132189)
  => 1 + 3 + 2 + 1 + 8 + 9
  => 24 ...
  => 2 + 4
  => 6
  
  digital_root(493193)
  => 4 + 9 + 3 + 1 + 9 + 3
  => 29 ...
  => 2 + 9
  => 11 ...
  => 1 + 1
  => 2
  """
  
  
  def digital_root(n):
      pass
  
  
  def main():
  	assert digital_root(16) == 7
  	assert digital_root(456) == 6
  	assert digital_root(942) == 6
  	assert digital_root(132189) == 6
  	assert digital_root(493193) == 2
  
  
  if __name__ == '__main__':
  	main()
  
subject: Add cw_sum_of_digits_digital_root.py