UnboundLocalError: local variable referenced before assignment

[svr]

Hi

Need some help here
Original code

def test1():
    test_list = []
    test_var = 0
    test_string1 = ""

    def test2():
        temp =2
        if temp > test_var:
            test_var = temp
        else:
            test_string = "fail"
        return test_string
    
    res = test2()
    print res

test1()

https://docs.python.org/3/faq/programming.html#why-am-i-getting-an-unboundlocalerror-when-the-variable-has-a-value

I used both global , nonlocal but both throws different error

def test1():
    test_list = []
    test_var = 0
    test_string1 = ""

    def test2():
        nonlocal test_var
        temp =2
        if temp > test_var:
            test_var = temp
        else:
            test_string = "fail"
        return test_string
    
    res = test2()
    print res

test1()

throws this error
nonlocal test_var ^
SyntaxError: invalid syntax

def test1():
    test_list = []
    test_var = 0
    test_string1 = ""

    def test2():
        global test_var
        temp =2
        if temp > test_var:
            test_var = temp
        else:
            test_string = "fail"
        return test_string
    
    res = test2()
    print res

test1()

throws this error ^
NameError: global name 'test_var' is not defined

Any suggestions ? I have gone through top 10 search results , all suggest to use nonlocal or global...