1、
>>> def a(): print("hello world!") >>> a <function a at 0x000002CE49DCB550>
>>> a() hello world!
2、
>>> def a(): print("hello world!") def b(): print("xxxxxx!") return b >>> a() hello world!
<function a.<locals>.b at 0x0000020074A8F040>
>>> a()() hello world! xxxxxx!
3、
>>> def a(): print("hello world!") def b(): print("xxxxxx!") return b() >>> a() hello world! xxxxxx!
4、
>>> x = 10
>>> def a(): global x x = 1000000 print(x) >>> a <function a at 0x000002787AF9B550>
>>> x 10
>>> a() 1000000
>>> x 1000000
小括號的作用表示執行函數。