title: Where do I add Graphviz's Executable on a Mac
body: <p>I'm trying to use <code>Graphviz</code> but am getting the error message:</p>
  
  <pre><code>graphviz.backend.ExecutableNotFound: failed to execute ['dot', '-Tpdf', '-O', 'test-output/aoc.gv.pdf'], make sure the Graphviz executables are on your systems' PATH
  </code></pre>
  
  <p>The code I am running is cut and pasted from the documentation:</p>
  
  <pre><code>from graphviz import Digraph, Graph
  dot = Digraph(comment='The Round Table')
  dot.node('A', 'King Arthur')
  dot.node('B', 'Sir Bedevere the Wise')
  dot.node('L', 'Sir Lancelot the Brave')
  dot.edges(['AB', 'AL'])
  dot.edge('B', 'L', constraint='false')
  dot.render('test-output/aoc.gv.pdf')
  </code></pre>
  
  <p>The file will output to the correct folder and the file is there and it has 170 bytes but it will not open. I have tried other extensions such as just 'gv' and they do not work either.  I'm using the latest version of <code>Graphviz</code> which is 0.10.1 and I have tried opening this file on a PC and it does not work on PC either (I have a Mac).  This problem is similar to</p>
  
  <p><a href="https://stackoverflow.com/questions/28312534/graphvizs-executables-are-not-found-python-3-4">Graphviz&#39;s executables are not found (Python 3.4)</a></p>
  
  <p>and</p>
  
  <p><a href="https://stackoverflow.com/questions/18438997/why-is-pydot-unable-to-find-graphvizs-executables-in-windows-8">Why is pydot unable to find GraphViz&#39;s executables in Windows 8?</a></p>
  
  <p>However, there are major stumbling blocks to my understanding these posts.  Number one, I have very little understanding of how Python is executed on a computer, so I really don't even know what an environment variable is. Second, when they refer to computer's PATH I can only assume that they're talking about the directory of the file which is executing the <code>Graphviz</code> module, but I'm not sure about that.  So I've added this line of code:</p>
  
  <pre><code>import sys
  str1 = "/library/frameworks/python.framework/versions/3.6/lib/python3.6/site-packages/graphviz/"
  sys.path.append(str1)
  </code></pre>
  
  <p>But that is not working.  Third, if I were to implement this step:</p>
  
  <blockquote>
    <p>Add this string to the end of your Variable value list (including semicolon): ;C:\Program Files (x86)\Graphviz2.34\bin</p>
  </blockquote>
  
  <p>Then I would have to translate that into its Mac counterpart and I'm not able to.  Any help would be appreciated.</p>