title: How to handle different versions of python protobuf
body: <p>My python package contains a lot of files compiled by python-protobuf (python2-protobuf-2.5.0 on Arch Linux), I installed the package on Ubuntu server 12.04.3 (which have python-protobuf-2.4.1), tried to run the code, and hit the following error:</p>
  
  <pre><code>from google.protobuf.internal import enum_type_wrapper
  ImportError: cannot import name enum_type_wrapper
  </code></pre>
  
  <p>I think it's because the protobuf modules in my package are compiled by protobuf-2.5.0 and they do not work with protobuf-2.4.1.</p>
  
  <p>I have no idea of the environments in which my code may run, the version of protobuf may vary.  How to make my package work with both protobuf 2.4 and 2.5?</p>
  
  <p>(A possible way: include two different sets of protobuf libraries (one compiled by 2.4.1, the other compiled by 2.5.0) in my package, get google.protobuf version at runtime and select the protobuf libraries to import.  Is it possible?</p>