instances:
def func():
x=10
def inner():
print(x)
return inner
a=func()
a() result of execute is 10
print(a()) result of execute is none :because the result is func() result no set return value so return None
closure operation:
in a inner function ,call enclosing function variable (not global variable),so inner fuction title term as closure operation.
closure operation can separate itself from that function environment
about closure operation:
closure operation =function module +the environment of define function.
def func():
print('good ')