title: No module named 'graphviz' in Jupyter Notebook
body: <p>I tried to draw a decision tree in Jupyter Notebook this way.</p>
  <pre><code>mglearn.plots.plot_animal_tree()
  </code></pre>
  <p>But I didn't make it in the right way and got the following error message.</p>
  <pre><code>---------------------------------------------------------------------------
  ModuleNotFoundError                       Traceback (most recent call last)
  &lt;ipython-input-65-45733bae690a&gt; in &lt;module&gt;()
        1 
  ----&gt; 2 mglearn.plots.plot_animal_tree()
  
  ~\Desktop\introduction_to_ml_with_python\mglearn\plot_animal_tree.py in plot_animal_tree(ax)
        4 
        5 def plot_animal_tree(ax=None):
  ----&gt; 6     import graphviz
        7     if ax is None:
        8         ax = plt.gca()
  
  ModuleNotFoundError: No module named 'graphviz
  </code></pre>
  <p>So I downloaded <a href="https://graphviz.gitlab.io/_pages/Download/Download_windows.html" rel="nofollow noreferrer">Graphviz Windows Packages</a> and installed it.</p>
  <p>And I added the PATH installed path(C:\Program Files (x86)\Graphviz2.38\bin) to USER PATH and (C:\Program Files (x86)\Graphviz2.38\bin\dot.exe) to SYSTEM PATH.</p>
  <p>And restarted my PC. But it didnt work. I still can't get it working.</p>
  <p>So I searched over the internet and got another solution that, I can add the PATH in my code like this.</p>
  <pre><code>import os
  os.environ[&quot;PATH&quot;] += os.pathsep + 'C:/Program Files (x86)/Graphviz2.38/bin'
  </code></pre>
  <p>But it didn't work.
  So I do not know how to figure it out now.</p>
  <p>I use the Python3.6 integrated into Anacode3.</p>
  <p>And I ALSO tried installing graphviz via PIP like this.</p>
  <pre><code>pip install graphviz
  </code></pre>
  <p>BUT it still doesn't work.</p>
  <p>Hope someone can help me, sincerely.</p>