Tkinter reference: a GUI for Python

Each widget has a set of options that affect its appearance and behavior—attributes such as fonts, colors, sizes, text labels, and such.

You can specify options when calling the widget's constructor using keyword arguments such as text="PANIC!" or height=20.

After you have created a widget, you can later change any option by using the widget's .config() method, and retrieve the current setting of any option by using the widget's .cget() method. See Section 19, “Universal widget methods” for more on these methods.