title: Python3 import error
body: <p>I have been confusing Python 3's difference from Python 2 about import. </p>
  
  <p>If I have such a directory like this...</p>
  
  <pre><code>module_test/ -&gt;
    a/hello.py
    lib/mad.py
  </code></pre>
  
  <p>And I want to import hello module from lib/mad.py</p>
  
  <p>So I wrote code like this..</p>
  
  <p>lib/mad.py</p>
  
  <pre><code>import a.hello
  </code></pre>
  
  <p>And I call python lib/mad.py ,but it happend ImportError.</p>
  
  <p>I don't know why it happen like this.</p>
  
  <p>Do you have any idea? I want to solve this question.</p>
  
  <p>Sample repository is <a href="https://github.com/okamurayasuyuki/module_test/tree/master/lib" rel="nofollow">https://github.com/okamurayasuyuki/module_test/tree/master/lib</a> . ##Thanks in advance. </p>