Radio buttons and checkboxes are quite commonly seen in a GUI. Radio buttons allow the user to select one option from a group, while checkboxes allow the user to select as many as they want. The "tkinter" module implements these via the "Radiobutton" and "Checkbutton" classes. Section 13.8 of the textbook covers the usage of radio buttons and checkboxes, but you can also find tutorials and references online. Some of the key things to keep in mind regarding them are: - The "variable" setting links a "Radiobutton" or a "Che ckbutton" to a Tk variable. - Commonly this is an "IntVar", but it can be a "StringVar" and so on. Every "Radiobut ton" in a group must link to the same variable, while each "Checkbut ton" should link to a different variable. - You can "set ()" the variable's value to match the value of a "Radiobut ton" or "Checkbut ton" in order to specify a default radio button selection or checkboxes that start out already checked. - The "value" setting of a "Radiobutton" defines what the variable is set to when you select that option. Every button in the group should have a different "value". - The "offvalue" and "onvalue" settings of a "Checkbutton" define what the variable is set to when the box is unchecked or checked. The "onvalue" is usually the relevant one. - To determine the value of a "Radiobutton" or if a "Checkbutton" is checked, read the value of the variable linked to it using the variable's "get ( )" method. Once you feel you have a grasp of how to use "Radiobutton" and "Checkbutton", try to implement the program depicted and described below: This program uses two labels, three radio buttons, three checkboxes and a button to create a GUI for specifying the details of a toasted sandwich. Some frames are also used for the layout. When the Submit Order button is pressed, one of two windows can appear: The code in the event handler for the button is not particularly complicated, but be sure to spend some time thinking about it and planning it before you jump in and start trying to code it