>>> def func(num): ... def func_in(): ... num += 1 ... print(num) ... return func_in ... >>> fun = func(10) >>> fun <function func.<locals>.func_in at 0x1034410d0> >>> fun() traceback (most recent call last): file "<stdin>", line 1, in <module> file "<stdin>", line 3, in func_in unboundlocalerror: local variable 'num' referenced before assignment
函数func_in的局部变量num未定义而引发的错误: local variable 'num' referenced before assignment
函数func_in即使定义在函数func中，但它的变量仍然是局部变量，与函数func的参数num不相关。
