new_contents: #!/usr/bin/env python
  from PyV8 import *
  
  firstSrc = "function hello(s) { return 'hello ' + s; }"
  firstPy = JSExtension("hello/javascript", firstSrc, register=False)
  firstPy.register()
  
  
  secondSrc = "native function title(s);"
  secondPy = JSExtension("title/python", secondSrc, lambda secondfunc: lambda name: "Mr. " + name, register=False)
  secondPy.register()
  
  with JSContext(extensions=['title/python', 'hello/javascript']) as ctx:
  	print ctx.eval("hello(title('flier'))")
  
subject: add example for extension