Your
self.tenlistchecks
contains a single element which is the array of tuples (double brackets):
[[(120, '21-08-2022', '1112', 'Alfa Romeo', 'james'), (122, '21-08-2022', '465', 'Buick', 'daniel '), (123, '21-08-2022', '789', 'Buick', 'daniel ')]]
^^
It should be:
[ (120, '21-08-2022', '1112', 'Alfa Romeo', 'james'), (122, '21-08-2022', '465', 'Buick', 'daniel '), (123, '21-08-2022', '789', 'Buick', 'daniel ')]
[EDIT]
Just as clarification it would probably be better to code it this way:
self.tenlistchecks = None
self.con = sqlite3.connect('car dealership.db')
self.cursorObj = self.con.cursor()
self.dashboard_buying_checks_dates = self.cursorObj.execute("select id, paymentdate , paymentvalue, car ,sellername from cars_buying_checks where nexttendays=?",(now,))
self.tenlistchecks = self.cursorObj.fetchall()
Also, I am not sure why you are using the
self.
prefix on variables that look to be local to this function, rather than members of the class.
[/EDIT]