new_contents: def p1_for(input_list):
      """Compute some of numbers in list with for loop."""
      out = 0
      for i in input_list:
          out += i
      return out
  
  
  def p1_while(input_list):
      """Compute some of numbers in list with while loop."""
      out = 0
      count = 0
      while count < len(input_list):
          out += input_list[count]
      return out
  
  
  def p1_rec(input_list, out=0):
      """Compute some of numbers in list with for loop."""
      if len(input_list) > 0:
          p1_rec(input_list[1:], out+input_list[0])
      else:
          return out
  
subject: Add p1.