python decorator

#!/usr/bin/python
# -*- coding: utf-8 -*-

def print_before_exec(func):
  def _(*args, **kwargs):
    print "decorated", args[0]
    return func(*args, **kwargs)
  return _

@print_before_exec
def double(x):
  print 2*x

if __name__ == "__main__":
  double(2)