Python：将数组索引附加到列表（.append）

Thanks ahead of time for the help. I am having trouble with appending an array index to a list. I Have an array counterStack which contains the starting point (1366, 1264) I run a neighborhood search on that starting point and for every new index that satisfies the conditions set the index should be appended to the counterStack. The strange thing is indices get properly appended to the list Thanks ahead of time for the help. I am having