formato de fecha de cambio de tkcalendar
from tkcalendar import DateEntry
import tkinter as tk
root = tk.Tk()
class CustomDateEntry(DateEntry):
def _select(self, event=None):
date = self._calendar.selection_get()
if date is not None:
self._set_text(date.strftime('%m/%d/%Y'))
self.event_generate('<<DateEntrySelected>>')
self._top_cal.withdraw()
if 'readonly' not in self.state():
self.focus_set()
entry = CustomDateEntry(root)
entry._set_text(entry._date.strftime('%m/%d/%Y'))
entry.pack()
root.mainloop()