Error when configuring tkinter widget: 'NoneType' object has no attribute

NoneType object has no attribute ... means that you have an object that is None, and you're trying to use an attribute of that object.

In your case you're doing q.get(...), so q must be None. Since q is the result of calling nse.get_quote(...), that function must have the possibility of returning None. You'll need to adjust your code to account for that possibility, such as checking the result before trying to use it:

q = nse.get_quote(stock)
if q is not None:
    print ...

The root of the problem is likely in how you're reading the file. stock will include the newline, so you should strip that off before calling nse.get_quote:

q = nse.get_quote(stock.strip())