python函数与方法装饰器

def fib_direct(n):
    assert n > 0, ‘invalid n‘
    if n < 3:
        return n
    else:
        return fib_direct(n - 1) + fib_direct(n - 2)

#! /usr/bin/env python
def shout(word=‘yes‘):
	return word.capitalize() + ‘!‘
print shout()

#outputs:Yes!

‘‘‘
As an object, you can assign the function to a variable like any other object.
Notece we don‘t use parentheses: we are not calling the function,
we are putting the function ‘shout‘ into the variable ‘scream‘.
‘‘‘
scream = shout
print scream()

#outputs:Yes!

‘‘‘
More than that, it meams you can remove the old name ‘shout‘,
and the function will still be accessible from ‘scream‘.
‘‘‘
del shout
try:
	print shout()
except NameError, e:
	print e
#outputs:name ‘shout‘ is not defined

print scream()
#outputs:Yes!