How to update urwid.Text widget dynamically?

Question

I'm working on TUI spotify player with urwid library and can't figure out how to update text with the name of playing track every time track is changed.

I have 2 widgets on the screen. First with liked tracks and second with currently playing track. I know about function currrent_playback but I don't understand how to get information that user changed a song and correspondingly text with currently playing song should be changed.

I came up with this function, but still don't understand how can I call it every time user changes track:

def get_current_playing_track(sp):
    playback = sp.current_playback()
    if playback and playback['is_playing']:
        return f"{playback['item']['artists'][0]['name']} | {playback['item']['name']}"
    else:
        return 'Nothing is playing now...'

Function for creating "liked tracks widget"

# right_part of the screen
def liked_tracks_widget(liked_tracks, sp):
    right_part = urwid.Overlay(liked_tracks, urwid.SolidFill(u'\N{MEDIUM SHADE}'),
    align='right', width=('relative', 50),
    valign='top', height=('relative', 90),
    min_width=20, min_height=9)

    return right_part

Function for displaying "currently playing track widget"

# lower part of the screen
def playing_track_widget(sp, playing_track):

    text_object = urwid.Text(playing_track)
    text_filler = urwid.Filler(text_object, 'bottom')
    frame = urwid.Frame(text_filler, footer=None)

    return frame

Main function, where I run urwid loop:

# main function for TUI
def run_tui(tracks, sp):
    liked_tracks = urwid.Padding(convert_to_ListBox(u'Liked Tracks', tracks.values(), sp), left=2, right=2)

    # updated state of currently playing track
    playing_track = get_current_playing_track(sp)

    # widget with liked tracks
    right_part = liked_tracks_widget(liked_tracks, sp)

    # widget with currently playing track
    lower_part = playing_track_widget(sp, playing_track)

    columns = urwid.Columns([
        ('weight', 1, lower_part),
        ('weight', 1, right_part)
        ], dividechars=1)

    main_loop = urwid.MainLoop(columns, unhandled_input=unhandled_input)

    main_loop.run()