new_contents: #!/usr/bin/env python
  
  """ Some tools for dealing with reversible numbers for problem 145 from Project Euler.
      https://projecteuler.net/problem=145
  """
  
  
  def is_odd(num):
      """ Check if an integer is odd. """
      if num % 2 != 0:
          return True
      else:
          return False
  
  
  def is_reversible(num):
      """ Check if a number is reversible given the above definition. """
      num_str = str(num)
      rev_num = int("".join(reversed(num_str)))
  
      total = num + rev_num
  
      for digit in str(total):
          if not is_odd(int(digit)):
              return False
  
      return True
  
  
  if __name__ == "__main__":
      # check some odd and even numbers
      assert is_odd(1), "1 should be odd"
      assert not is_odd(2), "2 should not be odd"
      assert not is_odd(100), "100 should not be odd"
      assert is_odd(10001), "10001 should be odd"
  
      # check the example reversible numbers
      assert is_reversible(36), "36 should be reversible"
      assert is_reversible(63), "63 should be reversible"
      assert is_reversible(409), "409 should be reversible"
      assert is_reversible(904), "904 should be reversible"
          
      print "all assertions passed"
  
subject: Add reversible related tools and tests.