As you probably saw in Chapter 15 and Chapter 16, you'll need to add a line each time you make a chart in order to render tooltips correctly:

chart = pygal.Bar()
chart.force_uri_protocol = 'http'

chart = pygal.Bar(style=my_style, x_label_rotation=45, show_legend=False)
chart.force_uri_protocol = 'http'

chart = pygal.Bar(style=my_style, x_label_rotation=45, show_legend=False)
chart.force_uri_protocol = 'http'