Getting the name of the class of the tabs of a Tkinter notebook

Question

In the following code I can access information in a notebook tab, in this case, the flag variable of the tab frame.
This can be useful in several situations; in my case, when I drop one of the tabs.
But it is perhaps easier to exemplify by binding to the NotebookTabChanged event, like so:

import tkinter as tk
from tkinter import ttk
import random


class FrameA(ttk.Frame):
    def __init__(self, parent, flag=0):
        ttk.Frame.__init__(self, parent)
        self.flag = flag
        self.label = ttk.Label(self, text="This is Frame A!\nThe flag is {}".format(self.flag))
        self.label.pack()


class FrameB(ttk.Frame):
    def __init__(self, parent, flag=1):
        ttk.Frame.__init__(self, parent)
        self.flag = flag
        self.label = ttk.Label(self, text="This is Frame B!\nThe flag is {}".format(self.flag))
        self.label.pack()


class App(tk.Frame):

    def __init__(self, parent):
        tk.Frame.__init__(self, parent)

        self.notebook = ttk.Notebook(parent)
        self.notebook.bind("<<NotebookTabChanged>>", self.tab_changed)
        self.tabs = []
        for i in range(6):
            frame = random.choice([FrameA, FrameB])
            j = random.choice(range(30))
            self.tabs.append(frame(self.notebook, flag=j))
            self.notebook.add(self.tabs[-1], text="Tab {}".format(i))

        self.notebook.pack(expand=True, fill='both')

    def tab_changed(self, event):
        i = self.notebook.index(self.notebook.select())
        print("{}".format(self.tabs[i].flag))


if __name__ == '__main__':
    root = tk.Tk()
    root.geometry('500x200+300+300')
    App(root)
    root.mainloop()

It could also be helpful to have access to which class (FrameA or FrameB) was used in the definition of the selected tab.
Can that be done?