title: Matplotlib AttributeError: 'NoneType' object has no attribute 'seq'
body: <p>I am trying to plot a bar chart and attach labels to each bar.  I can plot the chart with this code:</p>
  
  <pre><code>y = np.array([ 0.06590843,  0.10032079,  0.03295421,  0.12277632,  0.04257801,
          0.00641586,  0.05774278,  0.15106445,  0.13852435,  0.03732867,
          0.05570137,  0.11548556,  0.22834646,  0.09477982,  0.12569262,
          0.09711286,  0.05920093,  0.03295421,  0.11286089,  0.05453485,
          0.08486439,  0.09857101,  0.00641586])
  x= ['1', '2', '3', '4', '5', '6', '7', '8', '9', '10', '11', '20', '40', '60', '80', '100', '300', '500', '700', '900', '1000', '1300', '1512']
  plt.figure(figsize = (16, 2))
  plt.bar(range(23), y)
  </code></pre>
  
  <p>but when I try to add the labels with this:</p>
  
  <pre><code>plt.xticks(x)
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>AttributeError: 'NoneType' object has no attribute 'seq'
  </code></pre>
  
  <p>If I do: </p>
  
  <pre><code>plt.bar(x, y)
  </code></pre>
  
  <p>The x labels get jumbled and I get a figure like this:
  <a href="https://i.stack.imgur.com/rN25H.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/rN25H.png" alt="enter image description here"></a></p>
  
  <p>I am using %matplotlib inline for my backend.  </p>