title: python float division by zero when plotting treemap chart
body: <p>I'm new to python matplotlib and trying to plot a treemap chart, thanks in advance!</p>
  <pre><code>squarify.plot(sizes=df['vvmins'], label=df['category_name'], alpha=.8)
  plt.axis('off')
  plt.show()
  </code></pre>
  <p>then the 'float division by zero' error show up, my data set is like below(dummy):
  <a href="https://i.stack.imgur.com/HCmul.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HCmul.png" alt="enter image description here" /></a></p>