test_ab6.py.txt

testab.txt
ab AB
ab1 ONE
ab2 TWO
ab AC
ab13 THREE

$ python3 test_ab6.py 
Debug: ab 1 => ONE AB
Debug: ab 2 => TWO AB
ab 1 => ONE
ab 0 => 5
ab 2 => TWO
ab 3 => AB
ab 4 => AC
ab 13 => THREE