title: simple function, how to add to global path?
body: <p>I am trying to build out a set of custom functions I can reference in any .py file for my research project.</p>
  
  <p>If I place a very simple function in <code>D:\_coding\pyfun</code>, how can I get Python to reference this directory in all of my future scripts - so I can call the functions living there? My IDE is PyCharm if that matters.</p>
  
  <p>e.g., 
  <code>add.py</code> is saved in <code>D:\_coding\pyfun</code></p>
  
  <pre><code>def add(a, b):
      return a+b
  </code></pre>
  
  <p>And now when I call in Python, of course it doesn't recognize add</p>
  
  <pre><code>&gt;     add(1,3)
  &gt;     Traceback (most recent call last):
  &gt;       File "&lt;input&gt;", line 1, in &lt;module&gt;
  &gt;     NameError: name 'add' is not defined
  </code></pre>