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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def create_button_label(icon, font_size=constants.FONT_SIZE_NORMAL):
 """Create a button label with a chosen icon. :param icon: The icon :param font_size: The size of the icon :return: The created label """

    label = Gtk.Label()
    set_label_markup(label, '&#x' + icon + ';', constants.ICON_FONT, font_size)
    label.show()
    return label