# 在文件的开头定义全局变量
_a = 1
_b = 2
def add():
    global _a
    _a = 3
    return "_a + _b =", _a + _b
def sub():
    global  _b
    _b = 4
    return "_a - _b =", _a - _b
print (add())
print( sub())

bcbf389feb96a908bf6b36cb56de8fe1114c6ae9
<mask token>

<mask token>


def add():
    global _a
    _a = 3
    return '_a + _b =', _a + _b


def sub():
    global _b
    _b = 4
    return '_a - _b =', _a - _b


<mask token>

<mask token>


def add():
    global _a
    _a = 3
    return '_a + _b =', _a + _b


def sub():
    global _b
    _b = 4
    return '_a - _b =', _a - _b


print(add())
print(sub())

_a = 1
_b = 2


def add():
    global _a
    _a = 3
    return '_a + _b =', _a + _b


def sub():
    global _b
    _b = 4
    return '_a - _b =', _a - _b


print(add())
print(sub())

# 在文件的开头定义全局变量
_a = 1
_b = 2
def add():
    global _a
    _a = 3
    return "_a + _b =", _a + _b
def sub():
    global  _b
    _b = 4
    return "_a - _b =", _a - _b
print (add())
print( sub())
