Programmer info: Change system theme color into dark with 3 lines of python code

import gtk    
self.settings = gtk.settings_get_default()
self.settings.set_property("gtk-theme-name", "Adwaita-dark")

# get the system wide theme
        settings = gtk.settings_get_default()
        settings.props.gtk_button_images = True
        self.data.system_theme = settings.get_property("gtk-theme-name")
        # check for a local theme gtkrc file
        localtheme = os.path.join(CONFIGPATH,'%s_theme'%self.skinname)
        if os.path.exists(localtheme):
            print 'local theme path found'
            self.data.local_theme = 'Link to %s_theme'% self.skinname
            # make ~/.themes - quietly ignore the error if it exists
            try:
                os.makedirs(userthemedir)
            except OSError as exception:
                if exception.errno != errno.EEXIST:
                    raise
            # create systemlink because one can't store themes in an arbitrary folder.
            if not os.path.exists(userthemedir+'/%s'%self.data.local_theme):
                os.symlink(localtheme,userthemedir+'/%s'%self.data.local_theme)
            settings = gtk.settings_get_default()
            settings.set_string_property("gtk-theme-name", self.data.local_theme, "")
        else:
            self.data.local_theme = None