# create options menu
options = read_depots("depots.txt")
OptionMenu(app, depot, *options).pack()

In the above code I'M getting the error that __inti__ takes 4 arguments and that it's only given 3. I'M writing the code just how the book gives it to me.

Please give us a more complete snippet, including at least how app, depot and options are constructed. I am guessing that the problem is you have only one choice in the options list, and need two or more.