title: python3: ImportError: No module named xxxx
body: <p>I am new to Python and I am trying to understand a problem, which I see when creating a package. 
  I have the following file structure: (Working-Directory is /my/Python/jmLib2)</p>
  
  <pre><code>/my/Python/jmLib2
       |--- Phone
       |      |--- __init__.py
       |      |--- Pots.py
       |- Test2.py
  
  ---------------------------------
  cat ./jmLib2/Pots.py
  #!/usr/bin/python
  
  def Pots():
      print ("I'm Pots Phone")
  
  ---------------------------------
  cat ./jmLib2/__init__.py
  from Pots import Pots
  
  ---------------------------------
  cat ./Test2.py
  #!/usr/bin/python
  from Phone import Pots
  
  import os.path
  print ("OS:"+str(os.path))
  
  Pots()
  </code></pre>
  
  <hr>
  
  <p>When I now do: </p>
  
  <pre><code>python2 Test2.py
  OS:&lt;module 'posixpath' from '/usr/lib/python2.7/posixpath.pyc'&gt;
      I'm Pots Phone*
  </code></pre>
  
  <p>GREAT...BUT, if I do: </p>
  
  <pre><code>python3 Test2.py
  Traceback (most recent call last):
    File "Test2.py", line 2, in &lt;module&gt;
      from Phone import Pots
    File "/home/juergen/my/Python/jmLib2/Phone/__init__.py", line 1, in &lt;module&gt;
      from Pots import Pots
  ImportError: No module named 'Pots'
  </code></pre>
  
  <p>I am working with PyDev under Eclipse. PyDev reports me inside the <strong>init</strong>.py file an "Unresolved import: Pots"-error. 
  I have the same traceback-problem under PyDev and bash.</p>
  
  <p>Again, I am new to Python... so it is maybe a very stupid mistake.
  But can someone explain me, the difference between python2 and python3.4? 
  Do I have to modify the PYTHONPATH? Why?</p>
  
  <p>Greetings
  Juergen</p>