How can a tooltip be added to a GtkButton?

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To add a tooltip to a GtkButton in Python, first, import the necessary modules:

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk

Then, create a GtkButton and a GtkTooltip:

button = Gtk.Button(label="Click me")
tooltip = Gtk.Tooltip()

Next, set the tooltip text and attribute it to the button:

tooltip.set_markup("This button will do something when you click it")
button.set_tooltip_tooltip(tooltip) 

Finally, add the button to a GtkBox or GtkGrid, and show the tooltip when the user hovers over it:

box = Gtk.Box()
box.pack_start(button, True, True, 0)

def on_button_hover(widget):
    widget.get_tooltip().show()

button.connect("enter", on_button_hover)

window.add(box)
window.show_all()

This will create a GtkButton with a tooltip that appears when the user hovers over it.