Adding items to a listbox in Python using Entries from another class Python (tKinter)

I have created two classes, one is People.py (will be parent class) which contains a listBox that can be populated by just opening a file and adding content to the lisbox line by line.

Another class is Names.py (want it to be child class) which contains entries of first name, last name and a combobox for titles that should(will implement once question/problem is answered) go into the list in the main window where the class is People. I am trying to use an OOP model with this It's not fully OOP right now but will refactor the code later.

I have tried posting this code before but people are having trouble running it due to indentation problems after I past it on here so I'm providing the links to the classes without indentations issues here instead. They should run well. In Dropbox Name Class and People Class:

Note: I'm running this in a linux environment so you may have to modify the file choosing line in the People class if using windows or another OS.

    f = os.path.expanduser('~/Desktop')