title: How to import a function from python file by Boost.Python
body: <p>I am totally new to boost.python. 
  I reviewed a lot of recommending of using boost.python to apply with python, however still not easy to understand and find a solution for me.</p>
  
  <p>What I want is to import a function or class that directly from a python "SourceFile"</p>
  
  <p>Example File:
  Main.cpp
  MyPythonClass.py</p>
  
  <p>Let's says if there is a "Dog" class in "MyPythonClass.py" with "bark()" function, how do I get callback and send argument in cpp?  </p>
  
  <p>I have no idea what I should do!
  Please help me!</p>