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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 set_visible_graphs(self, visible_graph_list=None):
 """Show a column of the graph selected for display"""

        if visible_graph_list is None:
            visible_graph_list = self.visible_graph_list

        vline = urwid.AttrWrap(urwid.SolidFill(u'|'), 'line')

        graph_vector_column_list = []
        for state, graph, sub_title in zip(visible_graph_list,
                                           self.bar_graph_vector,
                                           self.sub_title_list):
            if state:
                text_w = urwid.Text(sub_title, align='center')
                sub_title_widget = urwid.ListBox([text_w])
                graph_a = [('fixed', 1, sub_title_widget),
                           ('weight', 1, graph)]
                graph_and_title = urwid.Pile(graph_a)
                graph_vector_column_list.append(('weight', 1, graph_and_title))
                graph_vector_column_list.append(('fixed', 1, vline))

        # if all sub graph are disabled
        if not graph_vector_column_list:
            self.visible_graph_list = visible_graph_list
            self.original_widget = urwid.Pile([])
            return

        # remove the last vertical line separator
        graph_vector_column_list.pop()

        y_label_a = ('weight', 1, urwid.Columns(graph_vector_column_list))
        y_label_and_graphs = [self.y_label,
                              y_label_a]
        column_w = urwid.Columns(y_label_and_graphs, dividechars=1)
        y_label_and_graphs_widget = urwid.WidgetPlaceholder(column_w)

        init_widget = urwid.Pile([('fixed', 1, self.title),
                                  ('weight', 1, y_label_and_graphs_widget)])

        self.visible_graph_list = visible_graph_list
        self.original_widget = init_widget