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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 on_gtk_prefer_dark_theme_toggled(self, chk):
 """Set the `gtk_prefer_dark_theme' property in dconf """

        self.settings.general.set_boolean('gtk-prefer-dark-theme', chk.get_active())
        select_gtk_theme(self.settings)