No idea what's causing this error "AttributeError: '_io.TextIOWrapper' object has no attribute 'tk'"

Question

The code keeps throwing the AttributeError: '_io.TextIOWrapper' object has no attribute 'tk' and I can't figure out what's causing it, I looked at other posts and nothing has helped me to get an idea of what's going on.

Below is the code that's causing it.

    def showhwk(lesson, popup):
        lesson = lesson.replace("/","")
        popup.withdraw()
        show = Tk()
        show.title("Homework marks for "+lesson)
        show.geometry("+{}+{}".format(positionRight, positionDown))
        try:
            with open(lesson+".csv", "r") as show:
                csvlist = list(csv.reader(show))
            for label in range (len(csvlist)):
                Label(show, text = "hello").grid(row = label)
        except FileNotFoundError:
            show.title("Error!")
            error = Label(show, text = "Homework file was not found")
            error.grid(row = 0)

        def goback3(show):
            popup.deiconify()
            show.withdraw()

        returnbut = Button(show, text = "Return", bg = "#79838e", command = lambda: goback3(show)).grid(row = 40, sticky = W+E)

This is the full error:

Traceback (most recent call last):
  File "C:\Users\Olek\AppData\Local\Programs\Python\Python38-32\lib\tkinter\__init__.py", line 1883, in __call__
    return self.func(*args)

  File "D:\Desktop\Folders\Python\Coursework\coursework code main.py", line 242, in <lambda>

show = Button(popup, text = "Show homework marks", bg = "green", command = lambda: showhwk(lesson, popup))

  File "D:\Desktop\Folders\Python\Coursework\coursework code main.py", line 278, in showhwk

Label(show, text = "hello").grid(row = label)

  File "C:\Users\Olek\AppData\Local\Programs\Python\Python38-32\lib\tkinter\__init__.py", line 3143, in __init__

Widget.__init__(self, master, 'label', cnf, kw)

  File "C:\Users\Olek\AppData\Local\Programs\Python\Python38-32\lib\tkinter\__init__.py", line 2561, in __init__

BaseWidget._setup(self, master, cnf)

  File "C:\Users\Olek\AppData\Local\Programs\Python\Python38-32\lib\tkinter\__init__.py", line 2530, in _setup

self.tk = master.tk

AttributeError: '_io.TextIOWrapper' object has no attribute 'tk'

Answer 1

You first define show like this:

show = Tk()

Later, you redefine show to be an open file handle with this statement:

with open(lesson+".csv", "r") as show:

Then, you try to use show as the master for a widget here:

Label(show, text = "hello").grid(row = label)

Because show is no longer a widget, it can't be used as the master for another widget. And that is why you get a tkinter error.