title: Pythonic method of determining if a list's contents change from odd to even values
body: <p>Writing some test cases and my mind wanders, assuming there is a better way to write something like this.  I have a list, its numbers transition from all odd values to all even, doesn't matter where.  I need to assert this is the case, here's what I came up with:</p>
  
  <pre><code>values = [1, 3, 5, 7, 5, 3, 5, 3, 5, 7, 4, 6, 8, 4, 2, 2, 8, 6]
  
  # find all the indexes of odd and even values
  odds = [i for (i, v) in enumerate(values) if v % 2 == 1]
  evens = [i for (i, v) in enumerate(values) if v % 2 == 0]
  
  # indexes should be a continuous sequence: 0, 1, 2, 3 ... n
  assert odds + evens == range(evens[-1] + 1)
  </code></pre>
  
  <p>Seems like a long way to go.  Suggestions on how this could be reduced?</p>