Pydvice: An attempt at bringing (defadvice) from Elisp to Python

Because the library can "advice" an existing function without decorating that function.

    # Write a function
    >>> def there():
    ...   print "there",
    ...
    >>> there()
    there
    
    # Write a peice of 'before advice' to run before the function
    #   New advice is activated by default
    >>> @pydvice.before(there)
    ... def hello():
    ...   print "Hello",
    ...
    
    # Note that active advice runs automatically on any function call
    >>> there()
    Hello there