Pytest, change counter that is passed to markers dynamically

Question

I am reading my test data from a Python file as follows.

//testdata.py -- its a list of sets.

TEST_DATA = [
(
{"test_scenario":"1"}, {"test_case_id":1}
),
(
{"test_scenario":"2"}, {"test_case_id":2}
)
]

Now I use this test data as part of a pytest test file.

// test.py
// import testdata

test_data = testdata.TEST_DATA   
start = 0

class TestOne():
    
     @pytest.mark.parametrize(("test_scenario,testcase_id"),test_data)
     @testcaseid.marktc[test_data[start][1]["test_case_id"]]
     def testfunction():
         global start
         start = start + 1
         // Doing test here. 

Now when I print start, it changes its value continuoulsy. But when I try to retrieve the pytest results, I still keep getting start = 0 due to which my test case ID isnt being recorded properly.

Can I either

1. Pass marker from within the function.
2. Or is there a way to change the count of start dynamically in this example?

P.S. This is the best way that I am able to store my test data currently.

Here's how i have my testcaseid.marktc defined. // testrailthingy.py

class testcaseid(object):

    @staticmethod
    def marktc(*ids):
        return pytest.mark.testrail(ids=ids)