new_contents: args = (xrange(100,1000))
  
  def problem_4(rng):
  
      def is_palindrome(x):
          return str(x) == str(x)[::-1]
      
      def permutate_pairs(S):
          for n, i in enumerate(S):
              for i2 in S[n::]:
                  yield i*i2
                  
      pairs = permutate_pairs(range(100,1000))
      return(max(filter(is_palindrome, pairs)))
  
subject: Create problem_4.py