title: Cannot find reference 'xxx' in __init__.py
body: <p>I have a project in PyCharm organized as follows:</p>
  <pre class="lang-none prettyprint-override"><code>-- Sources
     |--__init__.py
     |--Calculators
        |--__init__.py
        |--Filters.py
     |--Controllers
        |--__init__.py
        |--FiltersController.py
     |--Viewers
        |--__init__.py
        |--DataVisualization.py
     |--Models
        |--__init__.py
        |--Data
  </code></pre>
  <p>All of my <code>__init__.py</code>, except for the one right above <code>Sources</code> are blank files. I am receiving a lot of warnings of the kind:</p>
  <blockquote>
  <p>Cannot find reference 'xxx' in __init__.py</p>
  </blockquote>
  <p>For example, my <code>FiltersController.py</code> has this piece of code:</p>
  <pre class="lang-py prettyprint-override"><code>import numpy.random as npr
  
  bootstrap = npr.choice(image_base.data[max(0, x-2):x+3, max(0, y-2):y+3].flatten(), size=(3, 3), replace=True)
  </code></pre>
  <p>And I get this warning:</p>
  <blockquote>
  <p>Cannot find reference 'choice' in __init__.py</p>
  </blockquote>
  <p>I'm googling wondering what does this mean and what should I do to code properly in Python.</p>