title: python _2or3 module?
body: <p>I am writing a module to let me write code in python 3, but still run it in 2.  It looks surprisingly easy actually... anything else I should add?  From my (limited) flailing on the interactive interpreter, the future imports do not affect python 3 and are viewed as redundant.</p>
  
  <pre><code># _2or3.py
  '''
  Common usage:
  
  from __future__ import print_function, nested_scopes, division, absolute_import, unicode_literals
  from _2or3 import *
  '''
  
  import sys
  
  if sys.version[0] == '2':
     range = xrange
     input = raw_input 
  </code></pre>
  
  <p>Obviously there are some things you cannot do that you would normally be able to do in 3 (like dictionary compressions), and there are a few gotchas between the languages (like bytecodes.  It looks like you should NEVER use bytes)</p>
  
  <p>Any comments would be appreciated.</p>