Tkinter: AttributeError: NoneType object has no attribute <attribute name>

The grid, pack and place functions of the Entry object and of all other widgets returns None. In python when you do a().b(), the result of the expression is whatever b() returns, therefore Entry(...).grid(...) will return None.

You should split that on to two lines like this:

entryBox = Entry(root, width=60)
entryBox.grid(row=2, column=1, sticky=W)

That way you get your Entry reference stored in entryBox and it's laid out like you expect. This has a bonus side effect of making your layout easier to understand and maintain if you collect all of your grid and/or pack statements in blocks.

Change this line:

entryBox=Entry(root,width=60).grid(row=2, column=1,sticky=W)

into these two lines:

entryBox=Entry(root,width=60)
entryBox.grid(row=2, column=1,sticky=W)

Just as you already correctly do for grabBtn!

For entryBox.get() to access get() method you need Entry object but Entry(root, width=60).grid(row=2, column=1, sticky=W) returns None.

entryBox = Entry(root, width=60) creates a new Entry Object.

Moreover, you won't need entryBox = entryBox.grid(row=2, column=1, sticky=W) as it will rewrite entryBox with None

Just replace entryBox = entryBox.grid(row=2, column=1, sticky=W) with

entryBox = Entry(root, width=60)
entryBox.grid(row=2, column=1, sticky=W)

Alternative solution for Python3.8+ versions that allows to put all of this in one line using the walrus operator:

(entryBox := Entry(root, width=60)).grid(row=2, column=1, sticky=W)

Now entryBox will refer to the Entry widget and also get packed.

For chars per line management I can suggest sth like this:

(var := Button(
    text='fine', command=some_func, width=20, height=15, activebackground='grey'
)).grid(row=0, column=0, columnspan=0, rowspan=0, sticky='news')

But at that point might as well just do this "normally" (as suggested by other answers)

Sources:

• PEP 572 -- Assignment Expressions
• IMO great video explanation about walrus operator