函数调用中的双括号是什么意思？例如func（stuff）（stuff）？

def returnFunction():
    def myFunction():
        print(\'hello!\')
    return myFunction

>>> returnFunction()()
hello!

>>> result = returnFunction()
>>> result()
hello!

evaluation step 0: returnSomeFunction()()
evaluation step 1: |<-somefunction>-->|()
evaluation step 2: |<----result-------->|

codecs.getwriter(\'utf-8\')

StreamWriter

>>> codecs.getwriter(\'utf-8\')
<class encodings.utf_8.StreamWriter at 0x1004b28f0>

sys.stdout = StreamWriter(sys.stdout)

def funcwrapper(y):
    def abc(x):
        return x * y + 1
    return abc

result = funcwrapper(3)(5)
print(result)

def xyz(z):
    return z + 1

def funcwrapper(y):
    def abc(x):
        return x * y + 1
    return abc

result = funcwrapper(3)(xyz(4))
print(result)