title: Find the first non-consecutive number in a list
body: <p>The challenge is to find the first non-consecutive number in python. I have managed to do it with a library called more_itertools, but the challenge requires that no library be involved. How can I solve it?
  This is my code:</p>
  
  <pre><code>from more_itertools import consecutive_groups
  
  def first_non_consecutive(l):
      g = []
      for grp in consecutive_groups(l):
          g.append(list(grp))
      if len(g) &gt; 1:
          return g[1][0]
  </code></pre>