title: AttributeError: module 'matplotlib' has no attribute 'coolwarm'
body: <p>I am newly learning matplotlib. I have plotted some data in a surface plot. But without colors it looks monotonous. I have referred this matplotlib <a href="https://matplotlib.org/2.0.2/examples/mplot3d/surface3d_demo.html" rel="nofollow noreferrer">example document</a> and used the same code for plotting. I am getting the above mentioned error in this line</p>
  
  <pre><code>surf = ax.plot_surface(X, Y, Z, cmap=cm.coolwarm,
                         linewidth=0, antialiased=False)
  </code></pre>
  
  <p>I have tried upgrading the matplotlib module and still getting the same error. Could anyone help me in fixing this. Thank you in advance.</p>